Praziquantel is a trematodicide provided in tablet form for the oral treatment of schistosome infections and infections due to liver fluke. Praziquantel is 2-(cyclohexylcarbonyl)-1, 2,3,6,7, 11b-hexahydro-4H-pyrazino [2, 1-a] isoquinolin-4-one with the molecular formula; C19H24N2O2.
Praziquantel is a white to nearly white crystalline powder of bitter taste. The compound is stable under normal conditions and melts at 136-140°C with decomposition. The active substance is hygroscopic. Praziquantel is easily soluble in chloroform and dimethylsulfoxide, soluble inethanol and very slightly soluble in water.
How is this medication useful?
Praziquantel is used to kill intestinal tapeworms and some other types of parasites. The FDA (U.S. Food and Drug Administration) has approved praziquantel for use in dogs and cats for the treatment of tapeworms. The FDA allows veterinarians to prescribe and use products containing this drug in different species or for other conditions in certain situations. You and your veterinarian can discuss why this drug is the most appropriate choice.
Indications: Treatment of all stages of schistosomiasis caused by all Schistosoma species; treatment of infection (clonorchiasis and opisthorchiasis) due to liver flukes.
Schistosomiasis: Oral: 20 mg/kg/dose 3 times/day for 1 day at 4- to 6-hour intervals
Clonorchiasis/opisthorchiasis: Oral: 25 mg/kg/dose 3 times/day for 1 day at 4- to 6-hour intervals
Cysticercosis (unlabeled use): Oral: 50 mg/kg/day divided every 8 hours for 14 days (Takayanagui, 2004)
Tapeworms (unlabeled use): Oral: 5-10 mg/kg as a single dose (25 mg/kg for Hymenolepis nana) (Liu, 1996)
Mechanism of action
Praziquantel induces a rapid contraction of schistosomes by a specific effect on the permeability of the cell membrane. The drug further causes vacuolization and disintegration of the schistosome tegument protein
Pregnancy Category B
Reproduction studies have been performed in rats and rabbits at doses up to 40 times the human dose and have revealed no evidence of impaired fertility or harm to the fetus due to praziquantel. There are, however, no adequate and well-controlled studies in pregnant women.
An increase of the abortion rate was found in rats at three times the single human therapeutic dose. While animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Praziquantel appeared in the milk of nursing women at a concentration of about 1/4 that of maternal serum although it is not known whether a pharmacological effect is likely to occur in children. Women should not nurse on the day of Praziquantel treatment and during the subsequent 72 hours.
Safety in children under 4 years of age has not been established.
In general praziquantel is very well tolerated. Side effects are usually mild and transient and do not require treatment. The following side effects were observed generally in order of severity: malaise, headache, dizziness, abdominal discomfort with or without nausea, rise in temperature and, rarely, urticaria. Such symptoms can, however, also result from the infection itself. Such side effects may be more frequent and/or serious in patients with a heavy worm burden.