Fast Five Quiz: Common STDs

Michael Stuart Bronze, MD


January 17, 2019

According to most guidelines and recommendations, metronidazole is the treatment of choice for trichomoniasis. Single-dose therapy with 2 g orally is as effective as prolonged therapy with 500 mg twice daily for 7 days. Single-dose therapy increases drug adherence.

Treatment failure with metronidazole increased from 0.4% to 3.5% between 1999 and 2002. Reports now describe resistance to metronidazole approaching 5%-10%. If standard treatment with either single-dose or multidose therapy fails, guidelines recommend that a regimen of 2 g of oral metronidazole or tinidazole for 5 days may be considered. Metronidazole gel is effective in less than 50% of trichomoniasis cases and is not recommended to treat trichomoniasis.

Humans are the only known host of T vaginalis. Transmission occurs predominantly via sexual intercourse. The organism is most commonly isolated from vaginal secretions in women and urethral secretions in men. It has not been isolated from oral sites, and rectal prevalence appears to be low in men who have sex with men.

Nearly one half of infected females and nearly all infected males are asymptomatic. Frothy vaginal discharge, which is thought to be the classic presentation of trichomoniasis, may be observed in only 12% of patients with this infection.

Given the poor reliability of history and physical findings, diagnosis of trichomoniasis depends on laboratory testing. According to the CDC, providers should obtain laboratory tests in all women seeking care for vaginal discharge and women at high risk for STDs.

For more on trichomoniasis, read here.


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