Niclosamide

NICLOSAMIDE

Niclosamide is a second-line drug for the treatment of most tape-worm infections, but it is not available in the USA.

Basic Pharmacology

Niclosamide is a salicylamide derivative. It appears to be mini-mally absorbed from the gastrointestinal tract—neither the drug nor its metabolites have been recovered from the blood or urine.

Adult worms (but not ova) are rapidly killed, presumably due to inhibition of oxidative phosphorylation or stimulation of ATPase activity.

Clinical Uses

The adult dose of niclosamide is 2 g once, given in the morning on an empty stomach. The tablets must be chewed thoroughly and then swallowed with water.

A. Taenia saginata (Beef Tapeworm), T solium (Pork Tapeworm), and Diphyllobothrium latum (Fish Tapeworm)

A single 2 g dose of niclosamide results in cure rates of over 85% for D latum and about 95% for T saginata. It is probably equally effective against T solium. Cysticercosis can theoretically occur after treatment of T solium infections, because viable ova are released into the gut lumen after digestion of segments, but no such cases have been reported. 

B. Other Tapeworms

Most patients treated with niclosamide for Hymenolepsis diminuta and Dipylidium caninum infections are cured with a 7-day course of treatment; a few require a second course. Praziquantel is supe-rior for Hymenolepis nana (dwarf tapeworm) infection. Niclosamide is not effective against cysticercosis or hydatid disease.

C. Intestinal Fluke Infections

Niclosamide can be used as an alternative drug in the treatment of Fasciolopsis buski, Heterophyes heterophyes, and Metagonimus yokogawai infections. The standard dose is given every other dayfor three doses.

Adverse Reactions, Contraindications, & Cautions

Infrequent, mild, and transitory adverse events include nausea, vomiting, diarrhea, and abdominal discomfort. The consumption of alcohol should be avoided on the day of treatment and for 1 day afterward. The safety of the drug has not been established in preg-nancy or for children younger than 2 years of age.