What is the recommended treatment for trichomonas in adults, including pregnant women?

Treatment for Trichomonas

Recommended First-Line Treatment

The preferred treatment for trichomoniasis is metronidazole 500 mg orally twice daily for 7 days, which achieves cure rates of 90-95% and is superior to single-dose therapy. 1, 2

The CDC specifically recommends this 7-day regimen as the preferred first-line treatment over single-dose therapy because:

• The 7-day regimen demonstrates significantly better efficacy than single-dose treatment, with cure rates of 89% versus 81% at test-of-cure (relative risk 0.55, p<0.0001) 3
• Single-dose metronidazole 2 g orally is an acceptable alternative only when patient compliance with multi-day therapy is unreliable, when directly observed therapy can be provided, or when cost is a significant barrier 4
• The improved efficacy of the 7-day regimen holds regardless of bacterial vaginosis status 3

Alternative Treatment Option

Tinidazole 2 g orally as a single dose is FDA-approved for trichomoniasis and equally effective as metronidazole single-dose therapy (cure rate 95% versus 97.5%) 5, 6

Critical Management Requirements

Partner Treatment (Essential to Prevent Reinfection)

• All sexual partners must be treated simultaneously with the same regimen, regardless of symptoms or testing status 4, 1, 2
• Most infected men are asymptomatic carriers, making them unknowing vectors of transmission 4
• Failure to treat partners is the most common cause of treatment failure and reinfection 4, 2
• Patients must abstain from sexual intercourse until both partners complete treatment and are asymptomatic 4, 1, 2

Alcohol Avoidance

• Patients must avoid all alcohol during treatment and for at least 24 hours after the last dose to prevent severe disulfiram-like reactions 4

Treatment in Pregnancy

Pregnant women with trichomoniasis should be treated with metronidazole 2 g orally as a single dose, but only after the first trimester. 4, 1

• Metronidazole is contraindicated during the first trimester due to concerns about fetal organogenesis, as the drug crosses the placental barrier rapidly 4, 1, 2
• If symptomatic trichomoniasis presents during the first trimester, treatment must be delayed until the second trimester begins 4
• Treatment after the first trimester is warranted because trichomoniasis is associated with premature rupture of membranes and preterm delivery 4, 1
• The single 2 g dose is specifically recommended for pregnant women rather than the 7-day regimen to minimize total fetal drug exposure 4

Treatment Failure Algorithm

First Treatment Failure

• Re-treat with metronidazole 500 mg twice daily for 7 days 4, 1, 2

Second Treatment Failure

• Administer metronidazole 2 g once daily for 3-5 days 4, 1, 2

Persistent Failure

• Consult an infectious disease specialist for susceptibility testing after excluding reinfection 4, 1
• For confirmed metronidazole-resistant cases, high-dose tinidazole 2 g twice daily for 14 days (total dose 56 g) combined with a broad-spectrum antibiotic (doxycycline or ampicillin) and clotrimazole pessaries has shown 90% cure rates 7

Special Populations

HIV-Infected Patients

• Use the same treatment regimens as HIV-negative patients 1, 2

Metronidazole Allergy

• Patients with immediate-type allergy to metronidazole may require desensitization 1
• Effective alternatives are not readily available 1

Critical Pitfalls to Avoid

Topical Therapy

• Never use metronidazole gel for trichomoniasis treatment—it achieves less than 50% efficacy 4, 2
• Topical metronidazole fails to achieve therapeutic levels in the urethra and perivaginal glands 2
• Other topical antimicrobials have even lower cure rates (<50%) 4

Follow-Up

• Routine follow-up is unnecessary for patients who become asymptomatic after treatment 4, 1, 2
• Re-evaluate only if symptoms persist, considering reinfection or resistant infection 1, 2