TRICHOMONAS VAGINALIS VAGINAL INFECTION

Recommended regimen

• metronidazole, 2g orally, in a single dose

OR

• tinidazole, 2g orally, in a single dose.

The reported cure rate in women ranges from 82% to 88% but may be increased to 95% if sexual partners are treated simultaneously.

Alternative regimen

• metronidazole, 400 or 500mg orally, twice daily for 7 days⁴

OR

• tinidazole, 500mg orally, twice daily for 5 days.

⁴ Metronidazole is available in either 200mg or 250mg capsules.

Other 5-nitroimidazoles are also effective, both in single and in multiple dose regimens.

Note

Patients taking metronidazole or other imidazoles should be cautioned not to consume alcohol while they are taking the drug and up to 24 hours after taking the last dose.

Asymptomatic women with trichomoniasis should be treated with the same regimen as symptomatic women.

Management of sexual partners

All sexual partners should be notified and treated, and patients should be advised against sexual intercourse until both the index patient and the partner(s) are treated. Trichomoniasis is frequently asymptomatic in men but is increasingly recognized as a cause of symptomatic non-gonococcal, non-chlamydial urethritis. For treatment of trichomonas vaginalis urethritis, see below.

Follow-up

Patients should be asked to return after 7 days if symptoms persist. Reinfection should be carefully excluded. Patients not cured following initial treatment often respond favourably to repeat treatment with the 7-day regimen. Resistance to the 5-nitroimidazoles has been reported, and may be one cause of treatment failure.

Patients not cured with the repeated course of metronidazole may be treated with a regimen consisting of metronidazole 2g orally, daily, together with 500mg applied intravaginally each night for 3-7 days. Vaginal preparations of metronidazole are available in many parts of the world, but are only recommended for the treatment of refractory infections, not for the primary therapy of trichomoniasis. An alternative regimen consists of 400 or 500mg metronidazole orally, twice daily for 7 days.

TRICHOMONIASIS IN PREGNANCY

There is increasing evidence of an association between infection with T. vaginalis and adverse pregnancy outcomes (e.g. premature rupture of the membranes, low birth weight). Metronidazole is not recommended for use in the first trimester of pregnancy, though it can be used during the second and third trimesters⁵. The minimum effective dose (2g orally, in a single dose) should be used.

⁵ Data on the safety of metronidazole in pregnancy are limited and some countries (USA, Canada) recommend use of single dose metronidazole at any time during pregnancy. This is especially relevant in the case of trichomoniasis, where early treatment has the best chances of preventing adverse pregnancy outcomes.

Neonatal infections

Infants with symptomatic trichomoniasis or with urogenital colonization persisting past the fourth month of life should be treated with metronidazole.

Recommended regimen

• metronidazole, 5 mg/kg orally, 3 times daily for 5 days.

Trichomonas vaginalis urethritis

Recommended regimen

• metronidazole, 400 or 500mg orally, twice daily for 7 days

OR

• tinidazole, 500mg, orally twice daily for 5 days.