Trichomoniasis Management
First-Line Treatment
For women with trichomoniasis, metronidazole 500 mg orally twice daily for 7 days is the preferred regimen, with cure rates of approximately 90-95%. 1
For men with trichomoniasis, metronidazole 2 g orally as a single dose is the recommended first-line treatment, also achieving cure rates of 90-95%. 2
Why the Regimen Differs by Sex
The evidence shows that 7-day metronidazole therapy is superior to single-dose therapy in women, with treatment failure rates of 11% versus 19% respectively (p<0.0001). 3 This significant difference in efficacy justifies the longer course for women, despite the convenience of single-dose therapy. 3
For men, the single 2 g dose remains appropriate as cure rates range from 83-100% in published studies. 4
Alternative Regimen
Metronidazole 2 g orally as a single dose may be used as an alternative when medication adherence is assured, though it is less effective in women. 2, 1
Tinidazole 2 g orally as a single dose is FDA-approved for trichomoniasis and demonstrates equivalent efficacy to metronidazole single-dose therapy (95% vs 97.5% cure rates). 4, 5
Partner Management
All sexual partners must be treated simultaneously to prevent reinfection. 2, 1 This is non-negotiable, as failure to treat partners is the most common cause of recurrent infection. 6
- Patients must abstain from sexual activity until both they and their partners complete treatment and are asymptomatic. 2, 1
- Asymptomatic partners should be treated even without confirmatory testing, as the organism is difficult to isolate in asymptomatic males. 7
Critical Pitfalls to Avoid
Topical metronidazole gel has <50% efficacy and should NEVER be used for trichomoniasis. 2, 6 This is a common error that leads to treatment failure.
Alcohol must be avoided during treatment and for at least 24 hours after completing metronidazole due to disulfiram-like reactions causing nausea, vomiting, flushing, headache, and abdominal cramps. 2
Follow-Up
Routine follow-up is unnecessary for patients who become asymptomatic after treatment. 2, 1
If symptoms persist, consider reinfection (most common) or resistant infection. 2, 1
Treatment Failure Algorithm
First failure: Re-treat with metronidazole 500 mg twice daily for 7 days. 2, 1
Second failure: Administer metronidazole 2 g once daily for 3-5 days. 2, 1
Persistent failure after excluding reinfection:
- Consult infectious disease specialist. 2, 1
- Consider high-dose tinidazole 2 g twice daily for 14 days (total dose 56 g) combined with doxycycline or ampicillin plus clotrimazole pessaries, which achieves 90% cure rates in resistant cases. 8
Special Populations
Pregnancy
Metronidazole is contraindicated in the first trimester. 1 After the first trimester, treat with metronidazole 2 g orally as a single dose. 1
Treatment is important as trichomoniasis increases risk of premature rupture of membranes and preterm delivery. 1
HIV Infection
Use the same treatment regimens as for HIV-negative individuals. 2, 1
Metronidazole Allergy
Effective alternatives are extremely limited. 1 Patients with immediate-type allergy may require desensitization. 1 Tinidazole is an alternative nitroimidazole but may have cross-reactivity concerns. 4