Treatment of Trichomoniasis Vaginalis
The preferred treatment for Trichomoniasis vaginalis is metronidazole 500 mg orally twice daily for 7 days, which achieves cure rates of approximately 90-95%. 1
First-Line Treatment Options
- Metronidazole 500 mg orally twice daily for 7 days is the preferred regimen recommended by the Centers for Disease Control and Prevention 1
- An alternative regimen is metronidazole 2 g orally in a single dose, which may be preferred when medication adherence is a concern 2, 1
- Tinidazole 2 g orally in a single dose is also effective with cure rates comparable to metronidazole (95% vs 97.5% respectively) 3, 4
Management of Sex Partners
- All sexual partners should be treated simultaneously to prevent reinfection 2, 1
- Patients should avoid sexual intercourse until both they and their partners have completed treatment and are asymptomatic 1, 5
- Treating asymptomatic partners is essential as T. vaginalis is a sexually transmitted disease that can cause reinfection if partners remain untreated 6
Treatment Failure Management
- For first treatment failure, re-treat with metronidazole 500 mg twice daily for 7 days 2, 1
- For repeated failure, administer metronidazole 2 g once daily for 3-5 days 2, 5
- For metronidazole-resistant cases, a combination of high-dose tinidazole (2 g twice daily for 14 days) with a broad-spectrum antibiotic and clotrimazole pessaries has shown 90% efficacy in patients who attended follow-up 7
Important Clinical Considerations
- Metronidazole gel is NOT recommended for trichomoniasis treatment despite its approval for bacterial vaginosis, as its efficacy is considerably lower (<50%) compared to oral metronidazole 2, 8
- Routine follow-up is unnecessary for patients who become asymptomatic after treatment 2, 1
- Accurate diagnosis before treatment is important, using methods such as wet mount microscopy, culture, or nucleic acid amplification tests 1
Special Populations
Pregnancy
- Pregnant women can be treated with metronidazole 2 g orally in a single dose 2, 1
- Treatment is particularly important as trichomoniasis has been associated with adverse pregnancy outcomes, including premature rupture of membranes, preterm delivery, and low birthweight 2, 9
HIV Infection
- Patients with HIV infection should receive the same treatment regimen as HIV-negative individuals 2, 5
Metronidazole Allergy
- Patients with immediate-type allergy to metronidazole can be managed by desensitization 2, 1
- Topical therapy with drugs other than nitroimidazoles can be attempted in allergic patients, but cure rates are low (<50%) 2
Pitfalls and Caveats
- Failure to treat sexual partners is a common cause of recurrent infection 2, 6
- Metronidazole and tinidazole are the only effective drug class for trichomoniasis; alternatives have significantly lower efficacy 2, 8
- Screening and treatment should be considered before any reproductive tract surgery and during pregnancy to prevent complications 9
- Patients should be advised to avoid alcohol during treatment with metronidazole or tinidazole and for at least 24-72 hours afterward to prevent disulfiram-like reactions 1