hydroxyurea (Rx)

Brand and Other Names:Droxia, Hydrea, more...Siklos, hydroxycarbamide
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

capsules

  • 200mg
  • 300mg
  • 400mg
  • 500mg

Solid Tumors

Intermittent Therapy: 80 mg/kg PO q3day, OR  

Continuous Therapy: 20-30 mg/kg PO qDay

Head & Neck Tumors

Concomitant therapy with irradiation

  • 80 mg/kg PO q3days  
  • Begin 7 days prior to initiation of irradiation

Chronic Myelocytic Leukemia, Resistant

Continuous Therapy: 20-30 mg/kg PO qDay  

Sickle Cell Disease

Start: 15 mg/kg/day as single dose; monitor patient’s blood count every two weeks  

Titrate by 5 mg/kg/day q12wk

Dose is not increased if blood counts are between acceptable range and toxic

Not to exceed 35 mg/kg/day

Discontinue therapy until hematologic recovery if blood counts are considered toxic; may resume treatment after reducing dose by 2.5 mg/kg/day from dose associated with hematological toxicity

Thrombocythemia, Essential (Off-label)

15 mg/kg PO qDay  

Titrate to control platelets & maintain WBC count

HIV, Adjunct Treatment (Off-label)

500 mg PO BID

Use with antiretrovirals

Psoriasis (Off-label)

1000-1500 mg/day PO qDay-BID

Other Information

Monitor: CBC

Dosage Forms & Strengths

tablet

  • Siklos
    • 100mg
    • 1000mg (tripled-scored)

Sickle Cell Disease

Indicated to reduce the frequency of painful crises and to reduce the need for blood transfusions in children aged ≥2 years with sickle cell anemia with recurrent moderate-to-severe painful crises

<2 years: Safety and efficacy not established

2-18 years

  • Initial dose
    • 20 mg/kg PO qDay
    • Monitor blood counts q2weeks
  • Dose adjustment based on blood counts
    • Increase dose 5 mg/kg/day q8Weeks or if a painful crisis occurs Give until mild myelosuppression (absolute neutrophil count [ANC] 2,000/mcL to 4,000/mcL) is achieved, not to exceed 35 mg/kg/day
    • Increase dosing only if blood counts are in an acceptable range (see Dosage Modifications) or if a painful crisis occurs
    • Do not increase if myelosuppression occurs

Dosage Modifications

Hepatic impairment: Closely monitor hematologic parameters

Renal Impairment

  • CrCl ≥60 mL/min: No dosage adjustment necessary
  • CrCl <60 mL/min or end-stage renal disease (ESRD): Reduce dose to 10 mg/kg/day and closely monitor the hematologic parameters

Hematologic toxicities

  • Blood counts acceptable range
    • Neutrophils ≥2,000 cells/mm³
    • Platelets ≥80,000/mm³
    • Hemoglobin >5.3 g/dL
    • Reticulocytes ≥80,000/mm³ if hemoglobin <9 g/dL
  • Blood counts toxic range
    • Neutrophils <2,000 cells/mm³
    • Platelets <80,000/mm³ if hemoglobin <4.5 g/dL
    • Reticulocytes <80,000/mm³ if hemoglobin <9 g/dL
    • Younger patients with lower baseline counts may safely tolerate ANC down to 1,250/mm³
    • Discontinue treatment until hematologic recovery
  • Dosing after hematologic recovery
    • Reduce dose by 5 mg/kg/day from the dose associated with hematologic toxicity
    • May titrate up or down q8Weeks in 5 mg/kg/day increments
    • Patient should be at a stable dose with no hematologic toxicity for 24 weeks
    • Permanently discontinue treatment if a patient develops hematologic toxicity twice
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Interactions

Interaction Checker

and hydroxyurea

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            Contraindicated (0)

              Serious - Use Alternative (17)

              • adenovirus types 4 and 7 live, oral

                hydroxyurea decreases effects of adenovirus types 4 and 7 live, oral by Other (see comment). Avoid or Use Alternate Drug. Comment: Vaccination with live vaccines in a patient receiving hydroxyurea may diminish therapeutic effects of vaccines and increase risk of adverse effects (increased risk of infection).

              • BCG intravesical live

                hydroxyurea decreases effects of BCG intravesical live by Other (see comment). Avoid or Use Alternate Drug. Comment: Vaccination with live vaccines in a patient receiving hydroxyurea may diminish therapeutic effects of vaccines and increase risk of adverse effects (increased risk of infection).

              • BCG vaccine live

                hydroxyurea decreases effects of BCG vaccine live by Other (see comment). Avoid or Use Alternate Drug. Comment: Vaccination with live vaccines in a patient receiving hydroxyurea may diminish therapeutic effects of vaccines and increase risk of adverse effects (increased risk of infection).

              • cholera vaccine

                hydroxyurea decreases effects of cholera vaccine by immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug. Vaccination with live vaccines in a patient receiving hydroxyurea may diminish therapeutic effects of vaccines and increase risk of adverse effects (increased risk of infection).

              • deferiprone

                deferiprone, hydroxyurea. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid use of deferiprone with other drugs known to be associated with neutropenia or agranulocytosis; if an alternative is not possible, monitor absolute neutrophil count more frequently.

              • didanosine

                hydroxyurea, didanosine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Pancreatitis, hepatotoxicity, and peripheral neuropathy have occurred in HIV patients treated with hydroxyurea, and in particular, in combination with didanosine and/or stavudine, avoid this combination. .

              • influenza virus vaccine quadrivalent, intranasal

                hydroxyurea decreases effects of influenza virus vaccine quadrivalent, intranasal by Other (see comment). Avoid or Use Alternate Drug. Comment: Vaccination with live vaccines in a patient receiving hydroxyurea may diminish therapeutic effects of vaccines and increase risk of adverse effects (increased risk of infection).

              • measles mumps and rubella vaccine, live

                hydroxyurea decreases effects of measles mumps and rubella vaccine, live by Other (see comment). Avoid or Use Alternate Drug. Comment: Vaccination with live vaccines in a patient receiving hydroxyurea may diminish therapeutic effects of vaccines and increase risk of adverse effects (increased risk of infection).

              • measles, mumps, rubella and varicella vaccine, live

                hydroxyurea decreases effects of measles, mumps, rubella and varicella vaccine, live by Other (see comment). Avoid or Use Alternate Drug. Comment: Vaccination with live vaccines in a patient receiving hydroxyurea may diminish therapeutic effects of vaccines and increase risk of adverse effects (increased risk of infection).

              • palifermin

                palifermin increases toxicity of hydroxyurea by Other (see comment). Avoid or Use Alternate Drug. Comment: Palifermin should not be administered within 24 hrbefore, during infusion of, or within 24 hr after administration of antineoplastic agents. Coadministration of palifermin within 24 hr of chemotherapy resulted in increased severity and duration of oral mucositis.

              • rotavirus oral vaccine, live

                hydroxyurea decreases effects of rotavirus oral vaccine, live by Other (see comment). Avoid or Use Alternate Drug. Comment: Vaccination with live vaccines in a patient receiving hydroxyurea may diminish therapeutic effects of vaccines and increase risk of adverse effects (increased risk of infection).

              • smallpox (vaccinia) vaccine, live

                hydroxyurea decreases effects of smallpox (vaccinia) vaccine, live by Other (see comment). Avoid or Use Alternate Drug. Comment: Vaccination with live vaccines in a patient receiving hydroxyurea may diminish therapeutic effects of vaccines and increase risk of adverse effects (increased risk of infection).

              • stavudine

                hydroxyurea, stavudine. Either increases toxicity of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Pancreatitis, hepatotoxicity, and peripheral neuropathy have occurred in HIV patients treated with hydroxyurea, and in particular, in combination with didanosine and/or stavudine, avoid this combination. .

              • tofacitinib

                hydroxyurea, tofacitinib. Either increases toxicity of the other by immunosuppressive effects; risk of infection. Avoid or Use Alternate Drug.

              • typhoid vaccine live

                hydroxyurea decreases effects of typhoid vaccine live by Other (see comment). Avoid or Use Alternate Drug. Comment: Vaccination with live vaccines in a patient receiving hydroxyurea may diminish therapeutic effects of vaccines and increase risk of adverse effects (increased risk of infection).

              • varicella virus vaccine live

                hydroxyurea decreases effects of varicella virus vaccine live by Other (see comment). Avoid or Use Alternate Drug. Comment: Vaccination with live vaccines in a patient receiving hydroxyurea may diminish therapeutic effects of vaccines and increase risk of adverse effects (increased risk of infection).

              • zoster vaccine live

                hydroxyurea decreases effects of zoster vaccine live by Other (see comment). Avoid or Use Alternate Drug. Comment: Vaccination with live vaccines in a patient receiving hydroxyurea may diminish therapeutic effects of vaccines and increase risk of adverse effects (increased risk of infection).

              Monitor Closely (95)

              • abatacept

                hydroxyurea, abatacept. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of immunosuppression.

              • acalabrutinib

                acalabrutinib, hydroxyurea. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may increase risk of myelosuppressive effects.

              • adalimumab

                hydroxyurea, adalimumab. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of immunosuppression.

              • aldesleukin

                aldesleukin, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • alefacept

                hydroxyurea, alefacept. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of immunosuppression.

              • alemtuzumab

                alemtuzumab, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • allopurinol

                allopurinol, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • azacitidine

                azacitidine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • azathioprine

                azathioprine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • belatacept

                belatacept and hydroxyurea both increase immunosuppressive effects; risk of infection. Use Caution/Monitor.

              • belimumab

                hydroxyurea, belimumab. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of infection.

              • bendamustine

                bendamustine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • bupivacaine implant

                hydroxyurea, bupivacaine implant. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Local anesthetics may increase the risk of developing methemoglobinemia when concurrently exposed to drugs that also cause methemoglobinemia.

              • busulfan

                busulfan, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • carboplatin

                carboplatin, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • carmustine

                carmustine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • certolizumab pegol

                hydroxyurea, certolizumab pegol. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of immunosuppression.

              • chlorambucil

                chlorambucil, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • cidofovir

                cidofovir, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • cisplatin

                cisplatin, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • cladribine

                cladribine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • clofarabine

                clofarabine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • clozapine

                clozapine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Avoid combination. Combination may increase risk of myelosuppression.

              • cyclophosphamide

                cyclophosphamide, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • cytarabine

                cytarabine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • dacarbazine

                dacarbazine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • dactinomycin

                dactinomycin, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • dasatinib

                dasatinib, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • daunorubicin

                daunorubicin, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • decitabine

                decitabine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • dengue vaccine

                hydroxyurea decreases effects of dengue vaccine by immunosuppressive effects; risk of infection. Use Caution/Monitor. Immunosuppressive therapies (eg, irradiation, antimetabolites, alkylating agents, cytotoxic drugs, corticosteroids [greater than physiologic doses]) may reduce immune response to dengue vaccine.

              • denosumab

                hydroxyurea, denosumab. Other (see comment). Use Caution/Monitor. Comment: Combination therapy may lead to increased risk of infection.

              • dexrazoxane

                dexrazoxane, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • dichlorphenamide

                dichlorphenamide, hydroxyurea. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Both drugs can cause metabolic acidosis.

              • docetaxel

                docetaxel, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • doxorubicin

                doxorubicin, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • doxorubicin liposomal

                doxorubicin liposomal, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • echinacea

                echinacea decreases effects of hydroxyurea by Other (see comment). Use Caution/Monitor. Comment: Echinacea may decrease therapeutic effects of immunosuppressants.

              • epirubicin

                epirubicin, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • escitalopram

                escitalopram, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • estramustine

                estramustine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • etanercept

                hydroxyurea, etanercept. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of immunosuppression.

              • etoposide

                etoposide, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • fingolimod

                hydroxyurea increases effects of fingolimod by immunosuppressive effects; risk of infection. Modify Therapy/Monitor Closely. Concomitant therapy is expected to increase the risk of immunosuppression. Use caution when switching patients from long-acting therapies with immune effects. .

              • flucytosine

                flucytosine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • fludarabine

                fludarabine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • fluorouracil

                fluorouracil, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • ganciclovir

                ganciclovir, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • gemcitabine

                gemcitabine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • golimumab

                hydroxyurea, golimumab. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of immunosuppression.

              • idarubicin

                idarubicin, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • ifosfamide

                ifosfamide, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

                ifosfamide, hydroxyurea. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration with ifosfamide may increase the risk of immunosuppression and myelosuppression.

              • infliximab

                hydroxyurea, infliximab. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of immunosuppression.

              • influenza virus vaccine quadrivalent, cell-cultured

                hydroxyurea decreases effects of influenza virus vaccine quadrivalent, cell-cultured by Other (see comment). Use Caution/Monitor. Comment: Immunosuppressants may decrease the therapeutic effects of vaccines.

              • interferon alfa 2b

                interferon alfa 2b, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Cutaneous vasculitic toxicities (eg, vasculitic ulcerations and gangrene) were reported during therapy with hydroxyurea in patients with a history of, or currently receiving, interferon therapy.

              • interferon beta 1a

                interferon beta 1a, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Cutaneous vasculitic toxicities (eg, vasculitic ulcerations and gangrene) were reported during therapy with hydroxyurea in patients with a history of, or currently receiving, interferon therapy.

              • interferon gamma 1b

                interferon gamma 1b, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Cutaneous vasculitic toxicities (eg, vasculitic ulcerations and gangrene) were reported during therapy with hydroxyurea in patients with a history of, or currently receiving, interferon therapy.

              • irinotecan

                irinotecan, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • irinotecan liposomal

                irinotecan liposomal, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • ixabepilone

                ixabepilone, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • leflunomide

                hydroxyurea, leflunomide. Other (see comment). Use Caution/Monitor. Comment: Combination therapy may lead to increased risk of infection.

              • lenalidomide

                lenalidomide, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • lomustine

                lomustine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

                lomustine, hydroxyurea. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration with lomustine may increase the risk of immunosuppression and myelosuppression.

              • melphalan

                melphalan, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • mercaptopurine

                mercaptopurine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • methotrexate

                methotrexate, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • mitomycin

                mitomycin, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • mitoxantrone

                mitoxantrone, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • mycophenolate

                hydroxyurea, mycophenolate. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of immunosuppression.

              • natalizumab

                natalizumab, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Avoid combination. Potential for increased risk of concurrent infection.

              • nelarabine

                nelarabine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • ofatumumab SC

                ofatumumab SC, hydroxyurea. Either increases effects of the other by immunosuppressive effects; risk of infection. Use Caution/Monitor. Consider the risk of additive immune system effects when coadministering immunosuppressive therapies with coadministration. When switching from therapies with immune effects, take into account the duration and mechanism of action of these therapies when initiating ofatumumab SC.

              • oxaliplatin

                oxaliplatin, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • paclitaxel

                paclitaxel, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • paclitaxel protein bound

                paclitaxel protein bound, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • peginterferon alfa 2a

                peginterferon alfa 2a, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Cutaneous vasculitic toxicities (eg, vasculitic ulcerations and gangrene) were reported during therapy with hydroxyurea in patients with a history of, or currently receiving, interferon therapy.

              • pentostatin

                pentostatin, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • pralatrexate

                pralatrexate, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • probenecid

                hydroxyurea increases levels of probenecid by Other (see comment). Use Caution/Monitor. Comment: Dosage adjustment of probenecid may be needed.

              • procarbazine

                procarbazine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • pyrimethamine

                pyrimethamine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • siponimod

                siponimod and hydroxyurea both increase immunosuppressive effects; risk of infection. Use Caution/Monitor. Caution if coadministered because of additive immunosuppressive effects during such therapy and in the weeks following administration. When switching from drugs with prolonged immune effects, consider the half-life and mode of action of these drugs to avoid unintended additive immunosuppressive effects.

              • sipuleucel-T

                hydroxyurea decreases effects of sipuleucel-T by pharmacodynamic antagonism. Modify Therapy/Monitor Closely.

                hydroxyurea decreases effects of sipuleucel-T by Other (see comment). Use Caution/Monitor. Comment: Avoid combination. Immunosuppressants may decrease clinical efficacy of sipuleucel-T.

              • temozolomide

                temozolomide, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • teniposide

                teniposide, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • thioguanine

                thioguanine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • thiotepa

                thiotepa, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Avoid combination. Combination may increase risk of myelosuppression.

              • tocilizumab

                hydroxyurea, tocilizumab. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of infection.

              • topotecan

                topotecan, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • trastuzumab

                trastuzumab, hydroxyurea. Either increases toxicity of the other by immunosuppressive effects; risk of infection. Use Caution/Monitor. Neutropenia or febrile neutropenia incidence were increased when trastuzumab was coadministered with myelosuppressive chemotherapy. .

              • trastuzumab deruxtecan

                trastuzumab deruxtecan, hydroxyurea. Either increases toxicity of the other by immunosuppressive effects; risk of infection. Use Caution/Monitor. Neutropenia or febrile neutropenia incidence were increased when trastuzumab was coadministered with myelosuppressive chemotherapy. .

              • ustekinumab

                hydroxyurea, ustekinumab. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of infection.

              • vinblastine

                vinblastine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • vinorelbine

                vinorelbine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              • zidovudine

                hydroxyurea, zidovudine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of myelosuppression.

                zidovudine, hydroxyurea. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of myelosuppression.

              Minor (0)

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                Adverse Effects

                >10%

                Infections (39.8%)

                Other infections (22.7%)

                Bacterial infections (16%)

                Gastrointestinal disorders (13.1%)

                Neutropenia (12.6%)

                1-10%

                Viral infections (9.9%)

                Fever (7.7%)

                Thrombocytopenia (7.4%)

                Other gastrointestinal disorders (7.4%)

                Headache (7.4%)

                Vitamin D deficiency (6.2%)

                Other not SCD-related reactions (5.7%)

                Anemia (4.2%) Skin reactions (3.7%)

                Parvovirus B19 infections (3.7%)

                Other skin and subcutaneous tissue disorders (3.2%)

                Other nervous system disorders (2.7%)

                Respiratory thoracic and mediastinal disorders (2.7%)

                Constipation (2.5%)

                Nausea (2.5%)

                Other metabolic and nutrition disorders (2%)

                Weight gain (2%)

                Renal and urinary disorders (2%)

                Frequency Not Defined

                Nausea

                Vomiting

                Constipation

                Diarrhea

                Mucositis

                Acute pulmonary reactions (rare)

                Genetic mutation (long-term use)

                Myelosuppression

                Secondary leukemia (long-term use)

                Elevated BUN, Cr

                Hyperuricemia

                Renal failure

                Rash

                Hyperpigmentation

                Skin ulcer

                Gangrenous disorder

                Postmarketing Reports

                Infections and infestations: Parvovirus B19 infection

                Blood and lymphatic system disorders: bone marrow depression including neutropenia (<2 X 10^9/L), reticulocytopenia (<80 X 10Postmarketing Reports^9/L), macrocytosis, thrombocytopenia (<80 X 10^9/L), anemia (hemoglobin <4.5 g/dL); hemolytic anemia

                Gastrointestinal disorders: Nausea, gastrointestinal disturbances, vomiting, gastrointestinal ulcer, severe hypomagnesemia, stomatitis

                Hepatobiliary disorders: Elevation of hepatic enzymes

                Skin and subcutaneous tissue disorders: Skin reactions (oral, ungula and cutaneous pigmentation), oral mucositis, rash, melanonychia, alopecia, leg ulcers, cutaneous dryness, nail hyperpigmentation, atrophy of skin and nails, scaling, violet papules, cutaneous lupus erythematosus

                Renal and urinary disorders: Dysuria, elevations in blood urea nitrogen

                Immune disorders: Systemic lupus erythematosus

                Metabolism and nutrition disorders: Anorexia

                Nervous system disorders: Dizziness, drowsiness, disorientation, hallucinations, and convulsions

                Respiratory disorders: Diffuse pulmonary infiltrates, dyspnea, and pulmonary fibrosis, interstitial lung disease, pneumonitis, alveolitis, allergic alveolitis and cough

                Reproductive system and breast disorders: Oligospermia, azoospermia, amenorrhea

                General disorders: Fever, chills, malaise, edema, and asthenia

                Investigations: Weight gain

                Hypersensitivity: Drug-induced fever (pyrexia) (>39°C, >102°F) requiring hospitalization reported concurrently with gastrointestinal, pulmonary, musculoskeletal, hepatobiliary, dermatological or cardiovascular manifestations; onset typically occurred within 6 weeks of initiation and resolved upon discontinuation of hydroxyurea; upon re- administration fever re-occurred typically within 24 hours

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                Warnings

                Black Box Warnings

                Myelosuppression

                • Severe myelosuppression may occur
                • Do not give if bone marrow function is markedly depressed
                • Monitor blood counts at baseline and throughout treatment
                • Interrupt treatment and reduce dose as necessary

                Malignancies

                • Hydroxyurea is mutagenic and clastogenic, and causes cellular transformation to a tumorigenic phenotype, and is thus unequivocally genotoxic and a presumed transspecies carcinogen that implies a carcinogenic risk to humans; advise sun protection and monitor patients for malignancies
                • In patients receiving long-term hydroxyurea for myeloproliferative disorders, such as polycythemia vera and thrombocythemia, secondary leukemias have been reported
                • It is unknown whether this leukemogenic effect is secondary to hydroxyurea or is associated with the patients' underlying disease
                • The physician and patient must very carefully consider the potential benefits relative to the undefined risk of developing secondary malignancies
                • Advise sun protection and monitor patients for malignancies

                Contraindications

                Hypersensitivity

                Severe anemia, bone marrow depression

                WBC <2500/mm³, platelets <100,000/mm³

                Pregnancy, lactation

                Cautions

                Risk of cutaneous vasculitic toxicities in patients with myeloproliferative disorders, especially with history of or concurrent interferon therapy; avoid use in patients with wounds on the legs (leg ulcers)

                Erythrocyte abnormalities reported; self-limiting megaloblastic erythropoiesis reported early in treatment, unrelated to vitamin B12 or folic acid deficiency

                Hyperuricemia may occur; adequate hydration, dosage adjustment, or initiation of uricosuric agents may be necessary

                Interferes with analytical analyses of the enzymes (urease, uricase, and lactate dehydrogenase) used in the determination of urea, uric acid and lactic acid, rendering falsely elevated results

                Macrocytosis is often seen early in the course of treatment; morphologic change resembles pernicious anemia, but is not related to vitamin B12 or folic acid deficiency; prophylactic folic acid is recommended

                Skin cancer reported in patients receiving long-term therapy; advise protection from sun exposure and monitor for development of secondary malignancies

                Fetal harm may occur when hydroxyurea is administered to a pregnant woman (see Pregnancy)

                Hemolytic anemia

                • Cases of hemolytic anemia in patients treated for myeloproliferative diseases reported
                • Patients who develop acute jaundice or hematuria in presence of persistent or worsening of anemia should have laboratory tests evaluated for hemolysis (eg, measurement of serum lactate dehydrogenase, haptoglobin, reticulocyte, unconjugated bilirubin levels, urinalysis, and direct and indirect antiglobulin [Coombs] tests)
                • In the setting of confirmed diagnosis of hemolytic anemia and in absence of other causes, discontinue therapy

                Pulmonary toxicity

                • Interstitial lung disease including pulmonary fibrosis, lung infiltration, pneumonitis, and alveolitis/allergic alveolitis (including fatal cases) reported in patients treated for myeloproliferative neoplasm
                • Safety and effectiveness not established for use in treatment of myeloproliferative neoplasms and use not approved by the FDA
                • Monitor patients developing pyrexia, cough, dyspnea, or other respiratory symptoms frequently, investigate and treat promptly; discontinue therapy and manage with corticosteroids

                Myelosuppression

                • Evaluate hematologic status prior to and every two weeks during treatment
                • Provide supportive care and modify dose or discontinue therapy as needed
                • Recovery from myelosuppression is usually observed within 15 days when therapy is interrupted; resume therapy after interruption at a lower dose
                • Monitor hematologic parameters more frequently in patients with hepatic impairment receiving therapy

                Leukemia

                • Secondary leukemia reported in patients treated long-term for sickle cell disease; leukemia also reported in patients with sickle cell disease and no prior history of treatment with drug
                • All patients should be followed up on long-term basis with regular blood counts to detect development of leukemia

                Drug interactions overview

                • Pancreatitis, hepatotoxicity, and peripheral neuropathy have occurred when hydroxyurea was administered concomitantly with antiretroviral drugs, including didanosine and stavudine
                • Concomitant use with a live virus vaccine may potentiate the replication of the vaccine virus and/or may increase the adverse reactions of the vaccine virus and result in severe infections
                • Interference with uric acid, urea, or lactic acid assays may falsely elevate results in patients treated with hydroxyurea
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                Pregnancy & Lactation

                Pregnancy

                No data are available with the use of hydroxyurea in pregnant women Limited available data on hydroxyurea use during pregnancy are insufficient to inform drug-associated risks

                In case of an exposure to hydroxyurea of pregnant female patients or pregnant partners of male patients, treated by hydroxyurea, a careful follow-up with adequate clinical, biological and ultrasonographic examinations should be considered

                Based on findings in animals and humans, male fertility may be compromised by treatment; azoospermia or oligospermia has been observed in men; before initiating therapy, inform male patients about the possibility of sperm conservation

                Advise pregnant women of the potential risk to a fetus; verify the pregnancy status of females of reproductive potential prior to initiating therapy

                Advise females of reproductive potential to use effective contraception during and after treatment for at least 6 months after therapy; advise males of reproductive potential to use effective contraception during and after treatment for at least 1 year after therapy

                Animal data

                • In animal reproduction studies, hydroxyurea administration to pregnant rats and rabbits during organogenesis produced embryotoxic and teratogenic effects at doses 0.8 times and 0.3 times, respectively, the maximum recommended human daily dose on a mg/m² basis In rats and rabbits, fetal malformations were observed with partially ossified cranial bones, absence of eye sockets, hydrocephaly, bipartite sternebrae, and missing lumbar vertebrae

                Lactation

                Unknown whether hydroxyurea is excreted in human milk, the effects of hydroxyurea on the breastfed child, or the effects of hydroxyurea on milk production

                Because of the potential for serious adverse reactions in a breastfed child from hydroxyurea, including carcinogenicity, advise patients not to breastfeed during treatment

                Pregnancy Categories

                A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

                B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

                C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

                D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

                X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

                NA: Information not available.

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                Pharmacology

                Mechanism of Action

                The precise mechanism by which hydroxyurea produces its cytotoxic and cytoreductive effects is not known. However, various studies support the hypothesis that hydroxyurea causes an immediate inhibition of DNA synthesis by acting as a ribonucleotide reductase inhibitor, without interfering with the synthesis of ribonucleic acid or of protein.

                The mechanisms by which hydroxyurea produces its beneficial effects in patients with sickle cell anemia (SCA) are uncertain. Known pharmacologic effects of hydroxyurea that may contribute to its beneficial effects include increasing hemoglobin F levels in red blood cells (RBCs), decreasing neutrophils, increasing the water content of RBCs, increasing deformability of sickled cells, and altering the adhesion of RBCs to endothelium.

                Absorption

                Duration: up to 24 hr

                Peak Plasma Time: 1-4 hr

                Distribution

                Vd: 0.5 L/kg

                Protein binding: 75-80%

                Metabolism

                Metabolized (60%) by liver and GI tract

                Metabolites: CO2, urea

                Elimination

                Half-Life: 2-4 hr

                Excretion: Urine (40% of administered dose in sickle cell anemia patients)

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                Administration

                Oral administration

                Administer dose qDay, with a glass of water

                Do not split the Siklos 100 mg tablets into smaller parts

                Patients unable to swallow tablets: Disperse tablets immediately before use in a small quantity of water in a teaspoon

                Hydroxyurea is a cytotoxic drug

                Follow applicable special handling and disposal procedures

                Tablets

                Store at room temperature, 20-25°C (68-77°F); excursions permitted between 15- 30°C (59-86°F)

                Keep tightly closed

                Broken 1000 mg tablets must be stored in the bottle and must be used within 3 months

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                Images

                BRAND FORM. UNIT PRICE PILL IMAGE
                Hydrea oral
                -
                500 mg capsule
                hydroxyurea oral
                -
                500 mg capsule
                hydroxyurea oral
                -
                500 mg capsule

                Copyright © 2010 First DataBank, Inc.

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                Patient Handout

                Patient Education
                hydroxyurea oral

                HYDROXYUREA - ORAL

                (hi-DROX-ee-you-REE-uh)

                COMMON BRAND NAME(S): Droxia, Hydrea, Siklos

                WARNING: This medication decreases bone marrow function, an effect that may lead to a low number of blood cells such as red cells, white cells, and platelets. This effect can cause anemia, decrease your body's ability to fight an infection, or cause easy bruising/bleeding. Tell your doctor right away if you develop any of the following symptoms: signs of infection (such as sore throat that doesn't go away, cough, fever, chills), easy bruising/bleeding, pale skin, unusual tiredness.Hydroxyurea may cause other cancers (such as secondary leukemia, skin cancer). Protect your skin from the sun. Avoid prolonged sun exposure, tanning booths, and sunlamps. Use sunscreen and wear protective clothing when outdoors. Tell your doctor right away if you notice any symptoms of cancer, such as swollen glands, sudden weight loss, night sweats, or unusual skin growths/moles.

                USES: This medication is used by people with sickle cell anemia to reduce the number of painful crises caused by the disease and to reduce the need for blood transfusions. Some brands are also used to treat certain types of cancer (such as chronic myelogenous leukemia, squamous cell carcinomas).

                HOW TO USE: Read the Medication Guide if available from your pharmacist before you start taking hydroxyurea and each time you get a refill. If you have any questions, ask your doctor or pharmacist.Take this medication by mouth with or without food as directed by your doctor, usually once daily. The dosage is based on your weight, medical condition, lab results, and response to treatment. Your treatment may be stopped for a short time if your blood counts are too low. Keep all medical and lab appointments.Do not increase your dose or use this drug more often or for longer than prescribed. Your condition will not improve any faster, and your risk of serious side effects will increase.If you are using the capsules, swallow the them whole. Do not crush, chew, or open the capsules.If you are using the tablets, swallow your dose with a glass of water. Only split a tablet if it has a score line and your doctor has instructed you to do so. If you have trouble swallowing, you may dissolve the whole or split tablet in a small amount of water in a teaspoon and swallow it right away.Wash hands before and after handling the medication or its container. You and/or your caregiver should wear disposable gloves when handling this medication or its container. If powder from the tablet or capsule spills, wipe it up right away with a wet paper towel and throw away in a closed container such as a plastic bag. Clean the spill area right away with soap and water. Make sure not to breathe the powder from the tablets/capsules.Since this drug can be absorbed through the skin and lungs, women who are pregnant or who may become pregnant should not handle this medication or breathe the dust from the tablets/capsules.Tell your doctor if your condition does not get better or if it gets worse.

                SIDE EFFECTS: See also Warning Section.Nausea, vomiting, loss of appetite, mouth sores, diarrhea, or constipation may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.People using this medication may have serious side effects. However, you have been prescribed this drug because your doctor has judged that the benefit to you is greater than the risk of side effects. Careful monitoring by your doctor may decrease your risk.Tell your doctor right away if you have any serious side effects, including: skin problems (such as ulcers, darkened/blackened/reddened skin), mental/mood changes (such as confusion, hallucinations), seizures, shortness of breath, signs of kidney problems (such as change in the amount of urine).Get medical help right away if you have any very serious side effects, including: chest pain.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

                PRECAUTIONS: See also Warning section.Before taking hydroxyurea, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: kidney disease, liver disease, blood/bone marrow disorders (such as bone marrow suppression, neutropenia, thrombocytopenia, anemia), HIV infection, high uric acid level in the blood, radiation treatment.Hydroxyurea can make you more likely to get infections or may worsen any current infections. Avoid contact with people who have infections that may spread to others (such as chickenpox, measles, flu). Consult your doctor if you have been exposed to an infection or for more details.Do not have immunizations/vaccinations without the consent of your doctor. Avoid contact with people who have recently received live vaccines (such as flu vaccine inhaled through the nose).To lower the chance of getting cut, bruised, or injured, use caution with sharp objects like razors and nail cutters, and avoid activities such as contact sports.Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Older adults may be more sensitive to the side effects of this drug.It is unknown if this medication affects sperm. If you plan to father a child, discuss the risks and benefits of this medication with your doctor.Tell your doctor if you are pregnant or plan to become pregnant. You should not become pregnant while using hydroxyurea. Hydroxyurea may harm an unborn baby. Men with female partners of childbearing age should ask about reliable forms of birth control while using this medication and for 1 year after stopping treatment. Women of childbearing age should ask about reliable forms of birth control while using this medication and for 6 months after stopping treatment. If you or your partner becomes pregnant or may be pregnant, tell your doctor right away.Hydroxyurea passes into breast milk and may have undesirable effects on a nursing infant. Breast-feeding while using this drug is not recommended. Consult your doctor before breast-feeding.

                DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug include: didanosine, nalidixic acid, stavudine.This medication may interfere with certain laboratory tests, possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.

                OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose include: swelling/scaling of hands and feet.

                NOTES: Do not share this medication with others.Lab and/or medical tests (such as complete blood count, kidney/liver function) must be done before you start taking this medication and while you are taking it. Keep all medical and lab appointments.Your doctor may direct you to also take folic acid while you are taking hydroxyurea due to the risk of anemia. Ask your doctor for details.

                MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

                STORAGE: Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

                Information last revised August 2021. Copyright(c) 2021 First Databank, Inc.

                IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

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                Formulary

                FormularyPatient Discounts

                Adding plans allows you to compare formulary status to other drugs in the same class.

                To view formulary information first create a list of plans. Your list will be saved and can be edited at any time.

                Adding plans allows you to:

                • View the formulary and any restrictions for each plan.
                • Manage and view all your plans together – even plans in different states.
                • Compare formulary status to other drugs in the same class.
                • Access your plan list on any device – mobile or desktop.

                The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

                Tier Description
                1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
                2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
                3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
                4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
                5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
                6 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
                NC NOT COVERED – Drugs that are not covered by the plan.
                Code Definition
                PA Prior Authorization
                Drugs that require prior authorization. This restriction requires that specific clinical criteria be met prior to the approval of the prescription.
                QL Quantity Limits
                Drugs that have quantity limits associated with each prescription. This restriction typically limits the quantity of the drug that will be covered.
                ST Step Therapy
                Drugs that have step therapy associated with each prescription. This restriction typically requires that certain criteria be met prior to approval for the prescription.
                OR Other Restrictions
                Drugs that have restrictions other than prior authorization, quantity limits, and step therapy associated with each prescription.
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                Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.