Niclosamide is a teniacide ("tenia-" referring to tapeworm) in the anthelmintic

Anthelmintic

Anthelmintics or antihelminthics are drugs that expel parasitic worms from the body, by either stunning or killing them. They may also be called vermifuges or vermicides .-Pharmaceutical classes:...

 family especially effective against cestodes that infect humans. It is also used as a piscicide

Piscicide

A piscicide is a chemical substance which is poisonous to fish. The primary use for piscicides is to eliminate a dominant species of fish in a body of water, as the first step in attempting to populate the body of water with a different fish...

.It is stressed that while antihelmintics are a drug family used to treat worm infections, Niclosamide is used specifically to treat tapeworms and is not effective against worms such as pinworms or roundworms. It is a chewable tablet taken orally, dosage depending on type of worm and patient's age and/or weight. Niclosamide molecules are lethal to tapeworms upon contact.

Side effects

The medication can have side effects such as abdominal pain, anorexia, diarrhea, and emesis. Rarely, dizziness, skin rash, drowsiness, perianal itching, and an unpleasant taste.

Mechanism of action

According to an article in Nature, niclosamide uncouples oxidative phosphorylation in the tapeworm.