Pharmacology · Nitroimidazoles
Tinidazole !
A longer-acting relative of metronidazole, often given as a single dose for trichomoniasis and giardiasis. Alcohol is avoided for three days after.
Updated 2026-11-01
Mechanism of action
Tinidazole is a nitroimidazole prodrug. Inside anaerobic bacteria and protozoa its nitro group is reduced to reactive radicals that damage DNA and kill the cell.
- Diffuses into the microbe
- Its nitro group is reduced
- Radicals damage DNA
- The microbe dies
Pharmacokinetics
- Absorption
- Well absorbed by mouth; taken with food.
- Distribution
- Reaches breast milk; breastfeeding is paused for three days after a dose.
Indications
- Trichomoniasis (partners treated at the same time) Trichomoniasis →
- Bacterial vaginosis Bacterial vaginosis →
- Intestinal amoebiasis and amoebic liver abscess Amoebic liver abscess →
- Giardiasis
Adverse effects
Common
- Metallic or bitter taste
- Nausea, loss of appetite and tiredness
- Dizziness and headache
Contraindications
- Allergy to tinidazole or other nitroimidazoles
- Cockayne syndrome
Key interactions
- Alcohol and propylene glycol
- Disulfiram-like reaction; avoided during treatment and for three days after.
- Warfarin, lithium, phenytoin
- Their levels or effects may rise, as with metronidazole.
What is monitored
- Neurological symptoms
- Blood count with repeated courses
Administration and safety
- Taken with food to reduce stomach upset
- Tablets can be crushed in syrup for people who cannot swallow them
Nursing care
- Teach to avoid alcohol until three days after the last dose
- Explain the bitter taste
- Teach to report numbness, tingling or seizures
Pregnancy and breastfeeding
Animal studies showed little fetal harm; it is used in pregnancy when the benefit justifies the risk, since untreated genital infections also carry risks.
Test yourself
Think of the answer, then tap the question to see it.
How does tinidazole differ from metronidazole in practice?
It acts longer, so single-dose or short courses are common.
How long is alcohol avoided after tinidazole?
During treatment and for three days afterwards.
In which genetic syndrome are nitroimidazoles contraindicated?
Cockayne syndrome.
Related drugs
Related conditions
← Back to the class: Nitroimidazoles
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: DailyMed - TINIDAZOLE tablet (DailyMed (U.S. National Library of Medicine), 2026); Tinidazole: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.