Pharmacology · Nitroimidazoles
Secnidazole !
A long-acting nitroimidazole given once, as granules on soft food, for bacterial vaginosis and trichomoniasis.
Updated 2026-11-01
Mechanism of action
Like metronidazole, secnidazole is reduced inside anaerobic bacteria and Trichomonas to reactive radicals that damage DNA. Its long persistence in the body allows a single dose.
- Granules are swallowed with soft food
- The nitro group is reduced inside the microbe
- Radicals damage DNA
- The microbe dies
Pharmacokinetics
- Absorption
- Oral granules, sprinkled on soft food; reaches breast milk, so breastfeeding is paused for four days after the dose.
Indications
- Bacterial vaginosis Bacterial vaginosis →
- Trichomoniasis Trichomoniasis →
Adverse effects
Common
- Headache
- Nausea, vomiting and diarrhoea
- Metallic or unpleasant taste
Contraindications
- Allergy to secnidazole or other nitroimidazoles
Key interactions
- Alcohol and propylene glycol
- Nausea, vomiting, cramps, headache, sweating and flushing; avoided during treatment and for two days after.
What is monitored
- Symptoms after treatment
- Vaginal itching or discharge
Administration and safety
- The whole packet is sprinkled on applesauce, yogurt or pudding and eaten within half an hour
- Granules are not chewed or crushed
- The granules are not mixed into water or other liquids
Nursing care
- Teach the preparation of the granules
- Teach to avoid alcohol for two days after the dose
- Explain that sexual partners are treated in trichomoniasis
- Advise pausing breastfeeding for four days
Pregnancy and breastfeeding
Human data are limited; pregnancy is discussed before use.
Test yourself
Think of the answer, then tap the question to see it.
How is secnidazole taken?
As a single dose of granules sprinkled on soft food, not chewed.
For which two infections is it used?
Bacterial vaginosis and trichomoniasis.
How long is alcohol avoided after secnidazole?
During treatment and for two days afterwards.
Related drugs
Related conditions
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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Secnidazole: MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.