ampicillin/sulbactam (Rx)

Brand and Other Names:Unasyn
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

powder for solution

  • 1.5g (ampicillin 1g/sulbactam 0.5g)
  • 3g (ampicillin 2g/sulbactam 1g)
  • 15g (ampicillin 10g/sulbactam 5g)

Gynecologic Infections

1.5 g (1 g ampicillin + 0.5 g sulbactam) to 3 g (2 g ampicillin + 1 g sulbactam) IV/IM q6hr; not to exceed 12 g/day

Intra-Abdominal Infections

1.5 g (1 g ampicillin + 0.5 g sulbactam) to 3 g (2 g ampicillin + 1 g sulbactam) IV/IM q6hr; not to exceed 12 g/day

Skin & Skin Structure Infections

1.5 g (1 g ampicillin + 0.5 g sulbactam) to 3 g (2 g ampicillin + 1 g sulbactam) IV/IM q6hr; not to exceed 12 g/day

Orbital Cellulitis

3 g (2 g ampicillin + 1 g sulbactam) IV q6hr

Pelvic Inflammatory Disease

3 g (2 g ampicillin + 1 g sulbactam) IV q6hr

Pneumonia

Aspiration or community acquired: 1.5 g (1 g ampicillin + 0.5 g sulbactam) to 3 g (2 g ampicillin + 1 g sulbactam) IV q6hr for 5 or more days

Hospital acquired: 3 g IV q6hr for 5 or more days

Urinary Tract Infections

Pyelonephritis: 3 g (2 g ampicillin + 1 g sulbactam) IV q6hr for 14 days

Acute Bacterial Rhinosinusitis (Off-label)

Severe infection requiring hospitalization

1.5 g (1 g ampicillin + 0.5 g sulbactam) to 3 g (2 g ampicillin + 1 g sulbactam) IV q6hr for 5-7 days

Endocarditis (Off-label)

Enterococcus infection resistant to penicillin/susceptible to aminoglycosides: 3 g (2 g ampicillin + 1 g sulbactam) IV q6hr for 6 weeks if not aminoglycoside resistant; >6 weeks if aminoglycoside resistant

HACEK infection: 3 g (2 g ampicillin + 1 g sulbactam) IV q6hr for 4 weeks

Dosing Modifications

Renal impairment

  • CrCl 5-14 mL/min/1.73 m²: 1.5 g (1 g ampicillin + 0.5 g sulbactam) to 3 g (2 g ampicillin + 1 g sulbactam) IV q24hr
  • CrCl 15-29 mL/min/1.73 m²: 3 g (2 g ampicillin + 1 g sulbactam) IV q12hr
  • CrCl ≥ 30 mL/min/1.73 m²: No dose adjustment necessary

Dosage Forms & Strengths

powder for solution

  • 1.5g (ampicillin 1g/sulbactam 0.5g)
  • 3g (ampicillin 2g/sulbactam 1g)
  • 15g (ampicillin 10g/sulbactam 5g)

Skin Infections

>1 year (<40 kg): 200 mg/kg/day IV divided q6hr; not to exceed 14 days of therapy  

>1 year (>40 kg): 1.5 g (1 g ampicillin + 0.5 g sulbactam) to 3 g (2 g ampicillin + 1 g sulbactam) q6hr; not to exceed 12 g/day

Epiglottitis

Children and adolescents: 100-200 mg ampicillin/kg/day IV divided q6hr  

Mild/Moderate Infection

>1 month-1 year: 100-150 mg ampicillin/kg/day IV/IM divided q6hr  

>1 year: 100-200 mg ampicillin/kg/day IV/IM divided q6hr

Meningitis/Severe Infections

>1 month-1 year: 200-300 mg ampicillin/kg/day IV/IM divided q6hr  

>1 year: 200-400 mg ampicillin/kg/day IV/IM divided q6hr

Peritonsillar and Retropharyngeal Abscess

Children and adolescents: 200 mg ampicillin/kg/day IV divided q6hr  

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Interactions

Interaction Checker

and ampicillin/sulbactam

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      Serious - Use Alternative

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              Serious - Use Alternative (12)

              • BCG vaccine live

                ampicillin decreases effects of BCG vaccine live by pharmacodynamic antagonism. Contraindicated. Wait until Abx Tx complete to administer live bacterial vaccine.

              • cholera vaccine

                ampicillin, cholera vaccine. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Avoid coadministration of cholera vaccine with systemic antibiotics since these agents may be active against the vaccine strain. Do not administer cholera vaccine to patients who have received oral or parenteral antibiotics within 14 days prior to vaccination.

              • demeclocycline

                demeclocycline decreases effects of ampicillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Tetracyclines may interfere with the bactericidal action of penicillins. Monitor for decreased therapeutic effects of penicillins if concomitantly used with a tetracycline.

              • doxycycline

                doxycycline decreases effects of ampicillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Tetracyclines may interfere with the bactericidal action of penicillins. Monitor for decreased therapeutic effects of penicillins if concomitantly used with a tetracycline.

              • eravacycline

                eravacycline decreases effects of ampicillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Tetracyclines may interfere with the bactericidal action of penicillins. Monitor for decreased therapeutic effects of penicillins if concomitantly used with a tetracycline.

              • minocycline

                minocycline decreases effects of ampicillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Tetracyclines may interfere with the bactericidal action of penicillins. Monitor for decreased therapeutic effects of penicillins if concomitantly used with a tetracycline.

              • mycophenolate

                ampicillin, mycophenolate. Either increases levels of the other by decreasing renal clearance. Avoid or Use Alternate Drug.

              • omadacycline

                omadacycline decreases effects of ampicillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Tetracyclines may interfere with the bactericidal action of penicillins. Monitor for decreased therapeutic effects of penicillins if concomitantly used with a tetracycline.

              • oxytetracycline

                oxytetracycline decreases effects of ampicillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug.

              • sarecycline

                sarecycline decreases effects of ampicillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Tetracyclines may interfere with the bactericidal action of penicillins. Monitor for decreased therapeutic effects of penicillins if concomitantly used with a tetracycline.

              • tetracycline

                tetracycline decreases effects of ampicillin by pharmacodynamic antagonism. Avoid or Use Alternate Drug. Tetracyclines may interfere with the bactericidal action of penicillins. Monitor for decreased therapeutic effects of penicillins if concomitantly used with a tetracycline.

              • typhoid vaccine live

                ampicillin decreases effects of typhoid vaccine live by pharmacodynamic antagonism. Contraindicated. Wait until Abx Tx complete to administer live bacterial vaccine.

              Monitor Closely (30)

              • aspirin

                ampicillin, aspirin. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.

              • aspirin rectal

                ampicillin, aspirin rectal. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.

              • aspirin/citric acid/sodium bicarbonate

                ampicillin, aspirin/citric acid/sodium bicarbonate. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.

              • bazedoxifene/conjugated estrogens

                ampicillin will decrease the level or effect of bazedoxifene/conjugated estrogens by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

              • chloroquine

                chloroquine decreases levels of ampicillin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate doses by at least 2 hr.

              • choline magnesium trisalicylate

                ampicillin, choline magnesium trisalicylate. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

                ampicillin, choline magnesium trisalicylate. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.

              • deflazacort

                ampicillin and deflazacort both decrease serum potassium. Use Caution/Monitor.

              • dexlansoprazole

                dexlansoprazole will decrease the level or effect of ampicillin by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

              • dienogest/estradiol valerate

                ampicillin will decrease the level or effect of dienogest/estradiol valerate by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor. An alternate or additional form of birth control may be advisable during concomitant use.

              • esomeprazole

                esomeprazole will decrease the level or effect of ampicillin by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

              • ethinylestradiol

                ampicillin will decrease the level or effect of ethinylestradiol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

              • ibuprofen/famotidine

                ibuprofen/famotidine will decrease the level or effect of ampicillin by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

              • lansoprazole

                lansoprazole will decrease the level or effect of ampicillin by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

              • lanthanum carbonate

                lanthanum carbonate decreases levels of ampicillin by cation binding in GI tract. Use Caution/Monitor. Administer ampicillin at least 2 hr before or after lanthanum. Interaction applies to oral ampicillin.

              • levonorgestrel oral/ethinylestradiol/ferrous bisglycinate

                ampicillin will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor. Antibiotics may decrease hormonal contraceptive efficacy.

              • mestranol

                ampicillin will decrease the level or effect of mestranol by altering intestinal flora. Applies only to oral forms of hormone. Low risk of contraceptive failure. Use Caution/Monitor.

              • methotrexate

                ampicillin increases levels of methotrexate by decreasing renal clearance. Use Caution/Monitor. Increased serum concentrations of methotrexate with concomitant hematologic and gastrointestinal toxicity have been observed with concurrent administration of high or low doses of methotrexate and penicillins.

              • omeprazole

                omeprazole will decrease the level or effect of ampicillin by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

              • pantoprazole

                pantoprazole will decrease the level or effect of ampicillin by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

              • rabeprazole

                rabeprazole will decrease the level or effect of ampicillin by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

              • rose hips

                ampicillin, rose hips. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

              • sodium bicarbonate

                sodium bicarbonate will decrease the level or effect of ampicillin by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

              • sodium citrate/citric acid

                sodium citrate/citric acid will decrease the level or effect of ampicillin by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

              • sodium phenylacetate

                ampicillin, sodium phenylacetate. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

              • sodium picosulfate/magnesium oxide/anhydrous citric acid

                ampicillin decreases effects of sodium picosulfate/magnesium oxide/anhydrous citric acid by altering metabolism. Use Caution/Monitor. Coadministration with antibiotics decreases efficacy by altering colonic bacterial flora needed to convert sodium picosulfate to active drug.

              • sodium sulfate/potassium sulfate/magnesium sulfate/polyethylene glycol

                ampicillin and sodium sulfate/potassium sulfate/magnesium sulfate/polyethylene glycol both decrease serum potassium. Modify Therapy/Monitor Closely.

              • spironolactone

                ampicillin increases effects of spironolactone by unspecified interaction mechanism. Use Caution/Monitor. Hyperkalemia.

              • sulfasalazine

                ampicillin, sulfasalazine. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.

                ampicillin, sulfasalazine. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

              • warfarin

                ampicillin increases effects of warfarin by Other (see comment). Use Caution/Monitor. Comment: Decr vitamin K-producing intestinal flora may increase INR after a few days.

              • willow bark

                ampicillin, willow bark. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor.

              Minor (18)

              • allopurinol

                ampicillin, allopurinol. Mechanism: unknown. Minor/Significance Unknown. Increased incidence of rash.

              • atenolol

                ampicillin decreases levels of atenolol by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

              • azithromycin

                azithromycin decreases effects of ampicillin by pharmacodynamic antagonism. Minor/Significance Unknown.

              • bendroflumethiazide

                bendroflumethiazide increases effects of ampicillin by decreasing renal clearance. Minor/Significance Unknown. May increase side effects.

              • chloramphenicol

                chloramphenicol decreases effects of ampicillin by pharmacodynamic antagonism. Minor/Significance Unknown.

              • chlorothiazide

                chlorothiazide increases levels of ampicillin by decreasing renal clearance. Minor/Significance Unknown.

              • clarithromycin

                clarithromycin decreases effects of ampicillin by pharmacodynamic antagonism. Minor/Significance Unknown.

              • colestipol

                colestipol decreases levels of ampicillin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

              • didanosine

                didanosine will decrease the level or effect of ampicillin by increasing gastric pH. Applies only to oral form of both agents. Minor/Significance Unknown.

              • erythromycin base

                erythromycin base decreases effects of ampicillin by pharmacodynamic antagonism. Minor/Significance Unknown.

              • erythromycin ethylsuccinate

                erythromycin ethylsuccinate decreases effects of ampicillin by pharmacodynamic antagonism. Minor/Significance Unknown.

              • erythromycin lactobionate

                erythromycin lactobionate decreases effects of ampicillin by pharmacodynamic antagonism. Minor/Significance Unknown.

              • erythromycin stearate

                erythromycin stearate decreases effects of ampicillin by pharmacodynamic antagonism. Minor/Significance Unknown.

              • hydrochlorothiazide

                hydrochlorothiazide increases levels of ampicillin by decreasing renal clearance. Minor/Significance Unknown.

              • methyclothiazide

                methyclothiazide increases levels of ampicillin by decreasing renal clearance. Minor/Significance Unknown.

              • metolazone

                metolazone increases levels of ampicillin by decreasing renal clearance. Minor/Significance Unknown.

              • rifampin

                rifampin decreases levels of ampicillin by increasing metabolism. Minor/Significance Unknown.

              • roxithromycin

                roxithromycin decreases effects of ampicillin by pharmacodynamic antagonism. Minor/Significance Unknown.

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              Adverse Effects

              >10%

              IM injection site pain (16%)

              1-10%

              Diarrhea (3%)

              IV injection site pain (3%)

              Thrombophlebitis (3%)

              Rash ( < 2%)

              <1%

              Abdominal distention

              Black, "hairy" tongue

              Candidiasis

              Chest pain

              Chills

              Dysuria

              Edema

              Epistaxis

              Erythema

              Fatigue

              Flatulence

              Glossitis

              Headache

              Itching

              Malaise

              Mucosal bleeding

              Nausea

              Pseudomembranous colitis

              Seizure

              Tightness in throat

              Thrombocytopenia

              Urine retention

              Vomiting

              Postmarketing Reports

              Gastrointestinal disorders: Abdominal pain, cholestatic hepatitis, cholestasis, hyperbilirubinemia, jaundice, abnormal hepatic function, melena, gastritis, stomatitis, dyspepsia, and Clostridium difficile associated diarrhea

              Nervous system disorders: Convulsion and dizziness

              Respiratory, Thoracic and mediastinal disorders: Dyspnea

              Skin and subcutaneous tissue disorders: Toxic epidermal necrolysis, Stevens-Johnson syndrome, angioedema, acute generalized exanthematous pustulosis (AGEP), erythema multiforme, exfoliative dermatitis, and urticaria

              Immune disorders: Serious and fatal hypersensitivity (anaphylactic) reactions

              Cardiac disorders: Acute myocardial ischemia with or without myocardial infarction may occur as part of an allergic reaction

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              Warnings

              Contraindications

              Hypersensitivity to drug or components

              Patients with previous history of cholestatic jaundice/hepatic dysfunction associated with ampicillin sulbactam

              Cautions

              Use caution in patients with allergy to cephalosporins and carbapenems

              Adjust dose in renal failure

              Prolonged use is associated with fungal or bacterial superinfection

              Hepatic dysfunction, including hepatitis and cholestatic jaundice reported; hepatic toxicity is usually reversible; however, deaths have occurred; monitor hepatic function at regular intervals in patients with hepatic impairment

              A generalized dull red maculopapular rash may occur in 5-10% of children 3-14 days after initiating therapy; carefully evaluate the rash to differentiate a nonallergic ampicillin rash from a hypersensitivity reaction; it normally begins on the trunk and spreads over most of the body; it may be most intense at pressure areas, elbows, and knees

              Hepatotoxicity reported; monitor hepatic function at regular intervals in patients with hepatic impairment

              A high percentage of patients with infectious mononucleosis have developed rash during therapy; therapy is not recommended in these patients

              May cause severe skin reactions, such as toxic epidermal necrolysis (TEN), Stevens- Johnson syndrome (SJS), dermatitis exfoliative, erythema multiforme, and acute generalized exanthematous pustulosis (AGEP); if patients develop skin rash monitor closely and discontinued therapy if lesions progress

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              Pregnancy & Lactation

              Pregnancy category: B

              Lactation: Excreted in breast milk; use caution

              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

              Drug combination of beta-lactamase inhibitor with ampicillin; interferes with bacterial cell wall synthesis during active replication, causing bactericidal activity against susceptible organisms; alternative to amoxicillin when unable to take medication orally; covers skin, enteric flora, and anaerobes; not ideal for nosocomial pathogens.

              Absorption

              Ampicillin

              • Bioavailability: 30-40%
              • Peak plasma time: 1-2 hr (oral)

              Distribution

              Ampicillin

              • Protein bound: 15-25%
              • Blister and tissue fluids, bile, and CSF with inflamed meninges

              Sulbactam

              • Protein bound: 38%
              • Bile, blister, and tissue fluids

              Metabolism

              Ampicillin and sulbactam

              • Liver

              Elimination

              Ampicillin

              • Half-life: 1-1.8 hr (normal renal function); 7-20 hr (anuria/end-stage renal disease)
              • Excretion: Urine (90% within 24 hr)

              Sulbactam

              • Half-life: 1-1.3 hr
              • Excretion: Urine (75-85%)
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              Administration

              IV Incompatibilities

              Additive: Aminoglycosides, ciprofloxacin

              Y-site: Aminoglycosides, amiodarone, amphotericin B cholesteryl sulfate, ciprofloxacin, cisatracurium(?), diltiazem(?), idarubicin, nicardipine, ondansetron, sargramostim

              IV Compatibilities

              Solution: NS

              Additive: Aztreonam

              Y-site: Amifostine, aztreonam, bivalirudin, cefepime, dexmedetomidine, docetaxel, enalaprilat, etoposide PO4, famotidine, fenoldopam, filgrastim, fluconazole, fludarabine, gatifloxacin, gemcitabine, granisetron, heparin, Hextend, insulin, linezolid, meperidine, morphine, paclitaxel, remifentanil, tacrolimus, teniposide, theophylline, thiotepa, vancomycin

              IV/IM Preparation

              Reconstitute with SWI or 0.5% or 2% lidocaine injection (IM) to obtain a 250 mg ampicillin-125 mg sulbactam/mL solution

              IM: Use within 1 hr after preparation

              IV: Further dilute to 3-45 mg/mL with appropriate diluent

              Use NS for IV piggyback

              IV: Use within 8 hr after preparation

              IV/IM Administration

              Administer around-the-clock to promote less variation in peak and trough serum levels

              Slow IV injection over at least 10-15 min or infusion over 15-30 min

              IM: Deep into large muscle mass

              Storage

              Store intact vials <30°C

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              Formulary

              FormularyPatient Discounts

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              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.
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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.