Indications
Niclosamide is used to treat tapeworm infections of the intestine, including beef tapeworm (Taenia saginata), pork tapeworm (Taenia solium), fish tapeworm (Diphyllobothrium latum) and dwarf tapeworm (Hymenolepis nana).
How It Works
Niclosamide works inside the gut and is barely absorbed into the body. It stops the tapeworm from producing energy and taking in glucose, so the head (scolex) and segments of the worm die. The dead worm is partly digested and passed out in the stool.
Dosage and Administration
- Beef, pork and fish tapeworm, adults: 2 g as a single dose (usually 4 tablets of 500 mg), taken after a light breakfast.
- Dwarf tapeworm, adults: 2 g on the first day, then 1 g a day for the next 6 days.
Chew the tablets thoroughly or crush them and swallow with a little water. Children’s doses depend on body weight and are given as prescribed. For pork tapeworm, a doctor may advise a laxative about 2 hours after the dose to clear the dead worm segments quickly. Repeat treatment only if advised.
Interactions
No important drug interactions are known because very little is absorbed. Avoid alcohol on the day of treatment and for a day after, as it may increase absorption and side effects.
Contraindications
- Allergy to niclosamide.
- Not for other worm types such as roundworm or pinworm, where it does not work.
Side Effects
Side effects are uncommon and mild: nausea, vomiting, stomach pain, loss of appetite, diarrhoea, light-headedness, itching or rash.
Get urgent medical help for swelling of the face, lips or throat, difficulty breathing or a widespread rash. With pork tapeworm, see a doctor urgently if severe headache, seizures or vision problems develop, as these may signal larvae in the brain (cysticercosis), which needs separate treatment.
Pregnancy and Lactation
Niclosamide is poorly absorbed and is considered one of the safer tapeworm treatments, but in pregnancy it should be used only if the doctor decides treatment cannot wait. It is unlikely to reach breast milk in meaningful amounts; ask your doctor before use while breastfeeding.
Precautions and Warnings
- With pork tapeworm, eggs released from damaged segments may cause cysticercosis; good hand washing and a laxative, if advised, reduce this risk.
- Stool checks after treatment confirm that the infection has cleared.
- Wash hands after using the toilet and before eating; family members may also need checking.
- Cook beef, pork and fish thoroughly to prevent reinfection.
Overdose
Overdose is unlikely to be serious because little is absorbed, but it may cause stomach upset and vomiting. A laxative may be advised. Contact a doctor if a large amount has been taken.
Therapeutic Class
Anthelmintic; taeniacide (tapeworm medicine).
Storage
Store below 30°C in a dry place, away from light and out of the reach of children.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.