Treatment of Trichomoniasis
First-Line Treatment for Non-Pregnant Adults
The recommended treatment for trichomoniasis is metronidazole 2 grams orally as a single dose, which achieves cure rates of 90-95%. 1, 2
Alternative Regimen
- Metronidazole 500 mg orally twice daily for 7 days is an acceptable alternative, particularly when adherence to single-dose therapy is uncertain 1, 2, 3
- Recent evidence suggests the 7-day regimen may be superior to single-dose therapy in women, with failure rates of 11% versus 19% respectively 4
- However, CDC guidelines continue to endorse the single-dose regimen as first-line due to improved compliance and lower cost 1, 2
Other FDA-Approved Options
- Tinidazole 2 grams orally as a single dose is equally effective, with cure rates of 92-100% 5, 6
- Secnidazole 2 grams orally as a single dose offers favorable pharmacokinetics with a longer half-life 7
Treatment During Pregnancy
Metronidazole is absolutely contraindicated during the first trimester of pregnancy due to concerns about fetal organogenesis, as the drug crosses the placental barrier rapidly. 1, 2
Pregnancy-Specific Guidelines
- If symptomatic trichomoniasis presents during the first trimester, treatment must be delayed until the second trimester begins 1
- After the first trimester, treat with metronidazole 2 grams orally as a single dose 1, 2, 3
- The single-dose regimen is specifically recommended for pregnant women rather than the 7-day regimen to minimize total fetal drug exposure 1
- Treatment after the first trimester is warranted because trichomoniasis is associated with premature rupture of membranes and preterm delivery 1, 2
Breastfeeding Considerations
- Because metronidazole shows carcinogenic potential in rodent studies, a decision should be made whether to discontinue nursing or discontinue the drug 8
- Metronidazole is secreted in human milk in concentrations similar to plasma 8
Critical Partner Management
All sexual partners must be treated simultaneously with the same metronidazole regimen, regardless of symptoms, as most infected men are asymptomatic carriers. 1, 2, 3
- Failure to treat partners is the most common cause of treatment failure and reinfection 1, 2
- Patients must abstain from sexual intercourse until both partners complete treatment and are asymptomatic 1, 2, 3
- Most infected men are asymptomatic, making them unknowing vectors of transmission 1
Management of Treatment Failure
Stepwise Approach to Persistent Infection
- First recurrence: Re-treat with metronidazole 500 mg twice daily for 7 days 1, 2, 3
- Second failure: Metronidazole 2 grams orally once daily for 3-5 days 1, 2, 3
- Persistent failure: After excluding reinfection, consult an infectious disease specialist for susceptibility testing 1, 2, 3
Critical Pitfalls to Avoid
Topical metronidazole gel is NOT effective for trichomoniasis and should never be used, as it achieves less than 50% efficacy. 1, 2, 3
Additional Safety Warnings
- Patients must avoid all alcohol during treatment and for at least 24 hours after the last dose to prevent severe disulfiram-like reactions including nausea, vomiting, flushing, headache, and abdominal cramps 1, 3
- Topical antimicrobials other than metronidazole have even lower cure rates (<50%) 1
- Intravaginal metronidazole/miconazole combinations show promise but are not currently standard of care 9