Secnidazole: Uses, How to Take, Doses & Side Effects

Updated in April 2024

Secnidazole is a medication that is prescribed to eliminate various types of intestinal parasites, especially those that cause intestinal infections, such as amoebiasis and giardiasis. It can also be prescribed to treat trichomoniasis.

This medication can be obtained at the pharmacy with a prescription signed by your doctor.

The use of secnidazole should be avoided during breastfeeding or suspected pregnancy. It should not be taken during the first months of pregnancy or taken by anyone allergic to the components of the formula. You should consult your doctor before using secnidazole to avoid any possible side effects.

Woman holding pill to her mouth

Common uses

Secnidazole can be used for the treatment of:

  • Giardiasis, caused by Giardia lamblia parasites
  • Intestinal amoebiasis, caused by the presence of amoebas in the intestine
  • Hepatic amoebiasis, caused by Entamoeba histolytica parasites
  • Trichomoniasis, caused by Trichomonas vaginalis parasites

This medication can be taken every 6 months as a way to treat intestinal worms. Children, older adults and people who frequently eat outside the home are those most likely to have intestinal parasites and therefore can take this type of medication regularly throughout their lives, as long as it is medically approved.

Is secnidazole effective for yeast infections?

Secnidazole has no action against Candida albicans fungus, which causes yeast infections. Therefore it is not indicated for the treatment of yeast infections.

Also recommended: Yeast Infection Creams: 5 Types & How to Use

Nonetheless, the doctor may opt to prescribe secnidazole with association with tinidazole and tioconazole, which are antifungals that prevent the growth of the Candida albicans fungus. This combination can help to treat both yeast infections and other vaginal infections caused by Trichomonas vaginalis or Gardnerella vaginalis that may be present.

How to take

This medication should be taken orally with fluids after a meal, preferably in the evening, after dinner. The dose varies according to the problem to be treated and the patient's age:

1. Secnidazole oral suspension 30 mg/mL

The use of secnidazole in oral suspension of 30 mg/mL is indicated in cases of amoebiasis and giardiasis in children. It is prescribed at a dose of 30 mg/kg of body weight, per day, according to the following table:

Child's weight (in kilograms)

Dose of suspension (in mLs)

5 to 6 Kg (11 to 13.2 lb)

5 mL

7 to 11 Kg (15.4 to 24.2 lb)

10 mL

12 to 16 Kg (26.4 to 35.2 lb)

15 mL

17 to 21 Kg (37.4 to 46.2 lb)

20 mL

22 to 26 Kg (48.5 to 57.3 lb)

25 mL

27 to 30 Kg (59.5 to 66.1 lb)

30 mL

In cases of intestinal amebiasis and giardiasis, treatment is carried out in a single dose. Hepatic amoebiasis treatment should be carried out for 5 to 7 days, as advised by the pediatrician.

Secnidazole in the form of an oral suspension can be found in bottles containing 900 mg or 450 mg of secnidazole in powder form to be diluted before use.

To prepare the suspension, add 30 mL of filtered water to the 900 mg secnidazole bottle, or 15 mL of filtered water to the 450 mg secnidazole bottle. Shake the bottle vigorously for about 1 minute, so that the powder dissolves, and give the dose to the child using the measuring cup provided in the package.

The secnidazole suspension should be used immediately after preparation, and any unused amount of the suspension should be discarded after use.

2. Secnidazole 1000 mg tablet

Secnidazole 1000 mg can be found in packages containing 2 or 4 tablets. It is prescribed for the treatment of parasitic infections in adults, and doses are typically as follows: 

  • Trichomoniasis: 2 g (or 2 tablets of secnidazole 1000 mg) taken as a single dose. The same dose should be taken by other members in the household
  • Intestinal amebiasis and giardiasis: 2 g (2 tablets of secnidazole 1000 mg) taken as a single dose;
  • Hepatic amoebiasis: 1.5 g to 2 g of secnidazole per day. Treatment should last 5 to 7 days.

In any case, treatment should always be directed by a doctor to ensure that the dose used is adequate and that the infection is totally eliminated.

3. Secnidazole 500 mg tablet

Secnidazole in the form of 500 mg tablets is only indicated for use by adults, and the dosage varies according to the condition being treated:

  • Trichomoniasis: 4 tablets of secnidazole 500 mg, taken as a single dose. The same dose should be taken by other members in the household
  • Intestinal amebiasis and giardiasis: 4 tablets of secnidazole 500 mg taken as a single dose
  • Hepatic amoebiasis:1.5 g to 2 g of secnidazole per day. Treatment should last 5 to 7 days.

The use of secnidazole should always be directed by the doctor and based on the condition being treated.

Possible side effects

The most common side effects include fever, skin redness, itchy skin, nausea, stomach pain, dizziness, diarrhea, headache, or taste changes.

Contraindications for use

Secnidazole should not be used by children under 2 years of age, nor should it be taken during the first 3 months of pregnancy, if pregnancy is suspected or when breastfeeding.

Furthermore, this medication should also not be used by people who are allergic to any of the components in the formula or anyone who has severe liver failure.