Trichomoniasis is treated with a prescription antibiotic, typically metronidazole taken by mouth twice a day for seven days. It’s one of the most common curable sexually transmitted infections, and the right course of antibiotics clears it reliably. But successful treatment depends on more than just taking your pills: your sexual partners need treatment too, and the timing of follow-up testing matters.
Standard Treatment for Women and Men
The CDC-recommended regimen for women is metronidazole 500 mg taken orally twice daily for seven days. This seven-day course is preferred over the older single-dose approach because it produces better cure rates, particularly in women. Men have historically been treated with a single 2 g dose of metronidazole, though multi-day regimens are sometimes used depending on the clinical situation.
Tinidazole is a closely related antibiotic that works the same way and serves as an alternative, especially if you don’t tolerate metronidazole well or if the first round of treatment doesn’t clear the infection. Both drugs belong to the same class and kill the parasite by damaging its DNA. Tinidazole tends to cause fewer gastrointestinal side effects for some people, but it costs more and isn’t safe during pregnancy.
What to Avoid During Treatment
The most important restriction during treatment is alcohol. Both metronidazole and tinidazole can cause a severe reaction when combined with alcohol: intense nausea, vomiting, stomach cramps, headache, and facial flushing. You need to avoid all alcohol, including products containing propylene glycol, while taking the medication and for at least 72 hours after your last dose. Some labeling says 48 hours for metronidazole, but the safest recommendation is to wait a full three days.
You should also avoid sex for at least one week after both you and your partner have finished treatment. Having sex before then risks reinfection, even if your symptoms have already improved.
How Quickly Symptoms Improve
Most people notice their symptoms starting to ease within a few days of beginning antibiotics. Discharge, itching, irritation, and any burning with urination typically improve steadily over the course of the seven-day regimen. If your symptoms haven’t improved at all by the time you finish the full course, that’s worth flagging to your provider, as it could indicate reinfection or, less commonly, a resistant strain.
Keep in mind that roughly 70% of people with trichomoniasis never have noticeable symptoms at all. If you were diagnosed through routine screening rather than because of symptoms, you won’t have any changes to track. Treatment is still essential because the infection doesn’t go away on its own and can cause problems over time.
Why Your Partners Need Treatment Too
Treating only yourself is one of the most common reasons trichomoniasis comes back. Any sexual partner from the recent past needs to be treated at the same time, even if they feel fine. Since trichomoniasis is often symptomless (especially in men), a partner can easily carry the parasite without knowing it and pass it right back to you.
In some states, a practice called expedited partner therapy allows your provider to write a prescription for your partner without examining them first. This removes one of the biggest barriers to partner treatment, since many partners won’t schedule their own appointment. The availability of this option varies by state, so ask your provider whether it’s an option where you live.
Follow-Up Testing
Retesting after treatment is important because reinfection rates are high. The timing depends on the type of test and regimen used. If you completed the seven-day course of metronidazole, the earliest reliable time to retest with a nucleic acid test is three weeks after finishing treatment. For those who received a single-dose regimen, the wait is four weeks. Testing sooner can produce a false positive because remnants of the dead parasite’s genetic material may still be detectable.
Women living with HIV are specifically recommended to retest at three months after treatment, given the higher rates of reinfection and complications in this group.
Treatment During Pregnancy
Trichomoniasis during pregnancy is linked to premature rupture of membranes, preterm delivery, and low birth weight. Symptomatic pregnant women should be treated regardless of trimester. Metronidazole is the only recommended option during pregnancy. Although it does cross the placenta, multiple studies have found no evidence of birth defects or harmful effects on the developing baby.
Tinidazole is not safe during pregnancy. If you’re breastfeeding, metronidazole passes into breast milk in small amounts, and some clinicians suggest waiting 12 to 24 hours after treatment before nursing. For tinidazole, the wait is longer: 72 hours after a dose before breastfeeding.
Risks of Leaving It Untreated
Trichomoniasis isn’t just an uncomfortable infection. Left untreated, it increases the risk of acquiring HIV by two to three times. The parasite causes inflammation in the genital tract, which makes it easier for HIV to enter the body. One estimate found that roughly 746 new HIV cases among women in the United States each year are attributable to trichomoniasis alone.
For women already living with HIV, a concurrent trichomoniasis infection significantly raises the risk of pelvic inflammatory disease. Untreated trichomoniasis is also associated with higher rates of other STIs, likely because the inflammation it causes makes the body more vulnerable to additional infections.
When Standard Treatment Doesn’t Work
True resistance to metronidazole and tinidazole exists but is uncommon. If your symptoms persist after a full course and reinfection has been ruled out, your provider may try a higher dose or a longer course of the same medication. In many cases, what looks like treatment failure turns out to be reinfection from an untreated partner.
For genuinely resistant infections, higher-dose regimens of tinidazole over extended periods are sometimes used. These cases are rare enough that the CDC maintains a consultation service specifically for clinicians managing them. If you’re dealing with a persistent infection, the key steps are confirming the diagnosis with a sensitive test, ensuring all partners are treated, and working with a provider experienced in managing resistant cases.