Niclosamide (trade name Niclocide) is a teniacide in the anthelmintic family especially effective against cestodes that infect humans and many other animals. It is a salicyanilide compound (5-chloro-N-(2-chloro-4-nitrophenyl)-2-hydrobenzamide) also used as a piscicide. While antihelmintics are a drug family used to treat worm infections, niclosamide is used specifically to treat tapeworms and is not effective against other 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. It is not usually considered the drug of choice for treating cestode infection in humans or animals because of its side effects, though it remains highly effective and is generally inexpensive.
The medication can have side effects such as abdominal pain, anorexia, diarrhea, and emesis. Rarely, dizziness, skin rash, drowsiness, perianal itching, or an unpleasant taste occur. For some of these reasons, praziquantel is a preferable and equally effective treatment for tapeworm infestation.