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%) in women. 1

First-Line Treatment Regimen

Recommended regimen: Metronidazole 500 mg orally twice daily for 7 days 2, 3, 4

• This multi-day regimen demonstrates significantly better efficacy than single-dose treatment in the most recent high-quality randomized controlled trial 1
• Cure rates of 90-95% are achieved with this regimen 2, 3
• The 2018 trial showed 11% treatment failure with 7-day dosing versus 19% failure with single-dose therapy (p<0.0001) 1

Alternative regimen: Metronidazole 2 g orally as a single dose 2, 3, 5

• This remains an acceptable option when medication adherence is a significant concern 3
• Historically recommended as first-line, but recent evidence suggests inferior efficacy 1
• FDA-approved for trichomoniasis treatment 5

Second-line option: Tinidazole 2 g orally as a single dose 6

• Equally effective as single-dose metronidazole with 95-97.5% cure rates 7
• FDA-approved specifically for trichomoniasis 6
• Consider when metronidazole intolerance (not allergy) is present 6

Critical Management Principles

Partner treatment is mandatory:

• All sexual partners must be treated simultaneously to prevent reinfection 2, 3, 4
• Patients must abstain from sexual activity until both partners complete treatment and are asymptomatic 2, 3, 4
• Failure to treat partners is the most common cause of recurrent infection 4

Alcohol avoidance:

• Patients must avoid alcohol during treatment and for at least 24 hours after completing metronidazole 3
• Metronidazole causes a disulfiram-like reaction with alcohol (nausea, vomiting, flushing, headache, abdominal cramps) 3

Treatment Failure Algorithm

First treatment failure:

• Re-treat with metronidazole 500 mg twice daily for 7 days 2, 3, 4
• Ensure partner was treated and reinfection is excluded 2

Second treatment failure:

• Administer metronidazole 2 g once daily for 3-5 days 2, 3, 4
• Most strains with diminished susceptibility respond to higher doses 2

Persistent failure after appropriate therapy:

• Consult infectious disease specialist 3, 4
• Obtain susceptibility testing of T. vaginalis to metronidazole 2, 4
• CDC consultation is available for refractory cases 2

Special Populations

Pregnancy:

• First trimester: Metronidazole is contraindicated 2
• Second and third trimesters: Metronidazole 2 g orally as a single dose 2, 4
• Treatment is important as trichomoniasis is associated with premature rupture of membranes and preterm delivery 2, 4

HIV infection:

• Use the same treatment regimens as HIV-negative patients 2, 3, 4
• No dose adjustment required 3, 4

Metronidazole allergy:

• Effective alternatives are extremely limited 2, 4
• Desensitization may be required for true immediate-type allergy 3, 4
• Tinidazole is not appropriate as it may cross-react despite being a different nitroimidazole 8

Follow-Up Recommendations

• Routine follow-up is unnecessary for patients who become asymptomatic after treatment 2, 3, 4
• Re-evaluate only if symptoms persist, considering reinfection or resistant infection 3, 4

Common Pitfalls to Avoid

Do NOT use topical metronidazole gel:

• Topical preparations have efficacy <50% for trichomoniasis 3, 8, 4
• They fail to achieve therapeutic levels in the urethra and perivaginal glands 2
• This is only approved for bacterial vaginosis, not trichomoniasis 2, 5

Do NOT treat without partner notification:

• Trichomoniasis is a sexually transmitted infection requiring simultaneous partner treatment 2, 6
• Asymptomatic male partners should be treated even with negative cultures, as the organism is difficult to isolate from males 2