Tinidazole

About Tinidazole

Tinidazole kills certain parasites and bacteria. Its label covers trichomoniasis, a sexually transmitted infection, with a single 2 g dose, sexual partners taking the same dose at the same time; giardiasis, an intestinal infection, with a single 2 g dose; intestinal amebiasis with 2 g a day for three days, and amebic liver abscess for three to five days; and bacterial vaginosis in adult women who are not pregnant, at 2 g a day for two days or 1 g a day for five days, once other causes are ruled out. Children older than three can be treated for giardiasis and amebiasis at 50 mg/kg a dose, up to 2 g; its safety and effectiveness in other children have not been established.

The boxed warning explains that metronidazole, a structurally related drug, caused cancer in mice and rats treated long term; no such data have been reported for tinidazole, but because the two drugs are structurally related, its use is reserved for the approved conditions. It must not be taken by anyone who has had an allergic reaction to tinidazole or another nitroimidazole, or by people with Cockayne syndrome, in whom severe, irreversible liver injury, including fatal liver failure, has been reported with metronidazole; that contraindication was added to the Tindamax label in December 2021. Seizures and numbness or tingling in the hands or feet have been reported, and it is stopped promptly if such nerve symptoms appear. A vaginal yeast infection can follow treatment, and the label urges caution in people with a history of blood disorders. Common side effects are a metallic or bitter taste, nausea, tiredness, stomach upset, vomiting, loss of appetite, headache, dizziness and constipation.

Alcohol and products containing alcohol or propylene glycol are avoided during treatment and for three days afterward, since cramps, nausea, vomiting, headache and flushing may occur, and tinidazole is not given to anyone who has taken disulfiram in the past two weeks. Breastfeeding is not recommended during treatment or for 72 hours after the last dose. On pregnancy the labels differ: the Tindamax label says it should not be given in the first trimester, while a 2024 generic label says the available human data are insufficient to identify a risk of major birth defects or miscarriage; its use for bacterial vaginosis in pregnancy has not been studied. Animal studies suggest it may reduce male fertility. On hemodialysis, an extra half dose follows the session if that day’s dose was taken before it. A pharmacy can crush the tablets into cherry syrup for anyone who cannot swallow them.

Taking Tinidazole

How to take it

With food, which eases stomach upset, as a single dose or once a day for the days prescribed. Partners being treated for trichomoniasis take the same dose at the same time. If tablets cannot be swallowed, ask the pharmacy about crushing them into cherry syrup, and shake that liquid well before each dose.

If you miss a dose

Take it as soon as you remember, unless it is almost time for the next dose; then skip the missed dose and carry on as usual. Do not take a double dose.

Storage

At room temperature, tightly closed in the original container, away from heat, moisture and light, out of reach of children. A liquid made from crushed tablets keeps for seven days at room temperature; throw away what is left after that.

Interactions to know about

Avoid alcohol and products containing alcohol or propylene glycol during treatment and for three days after, and do not take it if you have taken disulfiram in the past two weeks. It can strengthen warfarin, so the warfarin dose may need adjusting during the course and for up to eight days after; lithium, phenytoin, cyclosporine, tacrolimus and fluorouracil may need monitoring or dose changes; cholestyramine is taken at a different time; and MedlinePlus advises asking the doctor about grapefruit and grapefruit juice.

This summarizes the official prescribing information. Your prescriber’s and pharmacist’s instructions, and the leaflet that comes with your medicine, take priority.

Why the cash price for Tinidazole differs from pharmacy to pharmacy

Most courses are a handful of tablets taken over one to five days, so each pharmacy’s dispensing fee and any minimum charge make up much of a quote, and small quantities are priced unevenly. A 2 g dose is four 500 mg tablets or eight 250 mg tablets, and the two strengths are priced separately.

Generic tinidazole is rated equivalent to Tindamax, but a pharmacy that does not stock it may need to order it, and a prescription that names Tindamax and blocks substitution is quoted at a brand price. Partners treated for trichomoniasis each have their own prescription, and each is quoted separately.

Ways to pay less for Tinidazole without insurance

• Ask for generic substitution, and compare more than one pharmacy.
• Check that each quote is for the strength written, and ask the prescriber whether 500 mg tablets would suit, since a 2 g dose then takes four tablets instead of eight.
• If tinidazole is hard to find or quoted high, ask the prescriber whether metronidazole, a related generic, would suit the infection.
• Upload the prescription to Script Unlock so licensed pharmacies can quote their cash price. You pay the pharmacy directly.

Questions to ask your pharmacist about Tinidazole

1. 1.How long after my last dose should I wait before drinking alcohol?
2. 2.Does my partner need to be treated at the same time?
3. 3.What should I know if I am pregnant, trying to become pregnant or breastfeeding?
4. 4.Does it interact with my warfarin, lithium or seizure medicine?

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