What is the recommended management of trichomoniasis, including first‑line therapy and dosing, treatment considerations in pregnancy, partner treatment, sexual abstinence recommendations, need for test‑of‑cure, and second‑line options if initial therapy fails?

Management of Trichomoniasis

For non-pregnant women, metronidazole 500 mg orally twice daily for 7 days is now the preferred first-line treatment, achieving superior cure rates (89%) compared to the traditional single 2-gram dose (81%), based on the highest-quality randomized controlled trial. 1

First-Line Therapy

Non-Pregnant Women

• Metronidazole 500 mg orally twice daily for 7 days is the recommended regimen, reducing treatment failure by 45% compared to single-dose therapy (relative risk 0.55, p<0.0001). 1
• The single 2-gram dose may be used when adherence to multi-day therapy is unreliable or cost is a barrier, but achieves lower cure rates (approximately 81-84%). 2, 1
• Both regimens achieve overall cure rates of 90-95% when sex partners are treated simultaneously. 3

Men

• Metronidazole 2 g orally as a single dose remains the preferred treatment for men. 4
• The 7-day regimen (500 mg twice daily) is an acceptable alternative. 2

Treatment During Pregnancy

Critical Timing Restrictions

• Metronidazole is absolutely contraindicated during the first trimester due to concerns about fetal organogenesis, as the drug crosses the placental barrier rapidly. 2
• If symptomatic trichomoniasis presents in the first trimester, treatment must be delayed until the second trimester begins. 2

After First Trimester

• Metronidazole 2 g orally as a single dose is recommended after 12 weeks gestation to minimize total fetal drug exposure. 2, 5
• Treatment is warranted because trichomoniasis is associated with premature rupture of membranes, preterm delivery, and low birth weight. 3, 2

Partner Treatment (Critical for Success)

All sexual partners must be treated simultaneously with the same metronidazole regimen, regardless of symptoms—this is non-negotiable. 2, 5

• Most infected men are asymptomatic carriers, making them unknowing vectors of transmission. 2
• Failure to treat partners is the most common cause of treatment failure and reinfection. 2, 5
• Partners should receive the same regimen as the index patient (7-day course for female partners, single dose acceptable for male partners). 2

Sexual Abstinence Requirements

• Patients must abstain from sexual intercourse until both they and their sex partners complete treatment and are asymptomatic. 3, 2, 5
• This prevents reinfection during the treatment period. 2

Alcohol Restriction

• Patients must avoid all alcohol during metronidazole treatment and for at least 24 hours after the last dose to prevent severe disulfiram-like reactions (flushing, nausea, vomiting, tachycardia). 2

Test-of-Cure Recommendations

• Follow-up is unnecessary for men and women who become asymptomatic after treatment. 3, 2
• Rescreening at 3 months after treatment is recommended due to high rates of repeat and persistent infections. 4

Management of Treatment Failure

First Failure

• Re-treat with metronidazole 500 mg orally twice daily for 7 days. 2, 5

Second Failure

• Administer metronidazole 2 g orally once daily for 3-5 days. 2, 5

Persistent Failure

• Consult an infectious disease specialist for susceptibility testing after confirming that reinfection from untreated partners has been excluded. 2, 5
• Even strains with reduced susceptibility generally respond to higher metronidazole doses. 2

Special Populations

HIV-Infected Patients

• HIV-infected patients should receive the same treatment regimen as HIV-negative patients. 3, 2, 5

Metronidazole Allergy

• No effective alternative antimicrobial exists; patients with confirmed metronidazole allergy may require desensitization protocols. 2

Critical Pitfalls to Avoid

• Never use topical metronidazole gel for trichomoniasis—it achieves less than 50% efficacy because it fails to reach therapeutic concentrations systemically. 2, 5
• Never treat pregnant women during the first trimester; defer therapy until after 12 weeks gestation. 2, 5
• Never omit simultaneous partner treatment; this is the primary driver of recurrent infection. 2, 5
• Do not use single-dose therapy as first-line in non-pregnant women when adherence to a 7-day regimen is feasible, as the longer course provides superior cure rates. 2, 1