Treatment for Trichomoniasis
The recommended first-line treatment for trichomoniasis is metronidazole 500 mg orally twice daily for 7 days, which achieves superior cure rates of 90-95% compared to single-dose therapy. 1, 2, 3
Primary Treatment Regimen
Metronidazole 500 mg orally twice daily for 7 days is the preferred regimen based on the most recent CDC guidelines and high-quality randomized controlled trial evidence showing better efficacy than single-dose therapy. 1, 2, 3
A 2018 randomized controlled trial of 623 women demonstrated that 7-day dosing resulted in significantly fewer treatment failures (11%) compared to single-dose therapy (19%), with a relative risk of 0.55 (p<0.0001). 4
Alternative regimen: Metronidazole 2 g orally as a single dose can be used when adherence to multi-day therapy is a concern, though it has lower efficacy. 5
Tinidazole 2 g orally as a single dose is FDA-approved and equally effective as single-dose metronidazole (95-97% cure rates), offering an alternative for patients who cannot tolerate metronidazole. 6, 7
Critical Management Principles
All sexual partners must be treated simultaneously to prevent reinfection, which is the most common cause of treatment failure. 1, 2, 3
Patients must abstain from sexual activity until both partners complete treatment and are asymptomatic. 1, 2, 3
Advise patients to avoid alcohol during treatment and for at least 24 hours after completion due to risk of disulfiram-like reaction (nausea, vomiting, flushing, abdominal cramps). 1
What NOT to Do
- Never use topical metronidazole gel for trichomoniasis - it has <50% efficacy because it fails to achieve therapeutic levels in the urethra and perivaginal glands where the organism resides. 5, 3, 8
Treatment Failure Algorithm
First treatment failure: Re-treat with metronidazole 500 mg twice daily for 7 days. 1, 2, 3
Second treatment failure: Administer metronidazole 2 g once daily for 3-5 days. 5, 1, 2
Persistent failure after excluding reinfection: Consult infectious disease specialist for possible resistant strains. 2, 3
Special Populations
Pregnancy
Metronidazole is contraindicated in the first trimester. 2, 3
After the first trimester, use metronidazole 2 g orally as a single dose (lower fetal exposure preferred). 2, 3
Treatment is important as trichomoniasis is associated with premature rupture of membranes and preterm delivery. 5, 2
HIV-Infected Patients
Metronidazole Allergy
For true immediate-type allergy, desensitization may be required as effective alternatives are extremely limited. 2
Patients with intolerance (not true allergy) to oral metronidazole should not be given vaginal metronidazole as it is ineffective. 5