What is the recommended treatment for trichomoniasis (Trichomonas infection)?

Treatment of Trichomoniasis

Metronidazole 500 mg orally twice daily for 7 days is the preferred treatment for trichomoniasis, as it achieves superior cure rates (89%) compared to single-dose therapy (81%) and should be used for all patients. 1

First-Line Treatment Regimen

• Metronidazole 500 mg orally twice daily for 7 days is the recommended regimen, with cure rates of approximately 90-95% in guideline-based studies 2, 3, 4
• This multi-dose regimen demonstrates significantly better efficacy than single-dose therapy in the highest quality randomized controlled trial (2018), reducing treatment failure by 45% (relative risk 0.55, p<0.0001) 1
• The 7-day regimen is particularly critical for women with prior trichomoniasis history (failure rate 24.1% with single-dose vs 12.6% with multi-dose) and symptomatic patients (failure rate 21.4% vs 10.8%) 5

Alternative Regimen

• Metronidazole 2 g orally as a single dose remains an acceptable alternative when medication adherence is a significant concern 6, 2
• Single-dose therapy achieves 80-95% cure rates in older studies but is inferior to 7-day therapy in the most recent high-quality evidence 1, 7, 8
• FDA has also approved metronidazole 375 mg twice daily for 7 days based on pharmacokinetic equivalency, though clinical data are limited 6

Alternative Agent: Tinidazole

• Tinidazole 2 g orally as a single dose is FDA-approved for trichomoniasis with cure rates of 92-100% 9
• Tinidazole demonstrates equivalent efficacy to metronidazole single-dose therapy (95% vs 97.5% cure rates) 10
• Consider tinidazole for patients with metronidazole intolerance or when single-dose therapy is preferred 9

Critical Management Principles

• All sexual partners must be treated simultaneously to prevent reinfection, which is the most common cause of treatment failure 6, 2, 3, 4
• Patients must abstain from sexual activity until both partners complete treatment and are asymptomatic 2, 3, 4
• Advise patients to avoid alcohol during treatment and for at least 24 hours after completing metronidazole therapy due to disulfiram-like reaction risk (nausea, vomiting, flushing, headache, abdominal cramps) 2

Treatment Failure Algorithm

When symptoms persist after initial treatment:

1. First treatment failure: Re-treat with metronidazole 500 mg twice daily for 7 days 6, 2, 3, 4
2. Second treatment failure: Administer metronidazole 2 g once daily for 3-5 days 6, 2, 3, 4
3. Repeated failure with reinfection excluded: Consult infectious disease specialist for possible resistant infection 2, 4

Follow-Up Recommendations

• Routine follow-up is unnecessary for patients who become asymptomatic after treatment 6, 2, 3, 4
• Test-of-cure at 4 weeks is recommended for women with prior trichomoniasis history given high posttreatment infection rates (24.1% with single-dose therapy) 5
• Re-evaluate only if symptoms persist, considering reinfection (most common) or resistant infection 2, 3, 4

Special Populations

Pregnancy

• Metronidazole is contraindicated in the first trimester of pregnancy 3, 4
• After the first trimester, use metronidazole 2 g orally as a single dose 3, 4
• Treatment is important as trichomoniasis is associated with premature rupture of membranes and preterm delivery 6, 4

HIV Infection

• Use the same treatment regimens as for HIV-negative patients 6, 2, 3, 4

Metronidazole Allergy

• For true metronidazole allergy, desensitization may be required as effective alternatives are limited 2, 4
• Tinidazole is a nitroimidazole with potential cross-reactivity and should be used cautiously 9

Common Pitfalls to Avoid

• Never use topical metronidazole gel for trichomoniasis—it has <50% efficacy and fails to achieve therapeutic levels in the urethra and perivaginal glands 6, 2, 3, 4
• Do not rely on patient-reported partner treatment—ensure partners are evaluated and treated to prevent reinfection 6
• Do not assume treatment failure is due to resistance—reinfection from untreated partners is far more common 3
• Self-reported adherence is high (96-99%) but does not guarantee cure, particularly with single-dose therapy 1