CDC Guidelines for Treatment of Trichomonas vaginalis in Men

First‑Line Pharmacologic Therapy

The CDC recommends a single oral dose of metronidazole 2 g for men with confirmed T. vaginalis infection. This regimen achieves cure rates of approximately 90‑95 % in clinical trials. 1
Metronidazole is the only oral anti‑trichomonal medication approved for use in the United States. 1

An alternative 7‑day regimen of metronidazole 500 mg taken orally twice daily provides efficacy comparable to the single‑dose regimen. 5

The majority of infected men are asymptomatic; infection is often detected through screening of contacts. 5

First failure: retreat with metronidazole 500 mg orally twice daily for 7 days. 1
Repeated failure: administer metronidazole 2 g orally once daily for 3–5 days. 1
Persistent failure: obtain expert consultation and perform susceptibility testing of the isolate. 1
Most metronidazole‑resistant strains can be overcome with higher dosing of metronidazole. 1

All sexual partners must receive concurrent treatment with the same metronidazole regimen. 1
Patients should abstain from sexual activity until both they and all partners have completed therapy and are asymptomatic. 1

Routine clinical follow‑up is unnecessary for men who become asymptomatic after treatment. 1
Test‑of‑cure is not required in asymptomatic men. 1

HIV‑infected men should be treated with the same metronidazole regimen as HIV‑negative men. 1
No effective oral alternatives exist for patients with a documented metronidazole allergy; desensitization protocols may be employed. 1

Topical metronidazole gel is ineffective for male trichomoniasis because therapeutic concentrations cannot be achieved in the urethra or peri‑urethral tissues; only oral metronidazole should be used. 1
Despite isolated reports of higher failure rates with single‑dose therapy in certain populations, CDC guidelines continue to endorse the 2 g single dose as the first‑line recommendation based on broader trial data. 1
The most common cause of apparent treatment failure is reinfection from untreated sexual partners; reinfection must be excluded before attributing failure to metronidazole resistance. 1