Pharmacotherapeutic group: Anthelmintics
ATC code: QP52AA51
Pharmacodynamics
Praziquantel is a pyrazinoisoquinoline derivative effective against tapeworms such as Dipylidium caninum, Echinococcus multilocularis, and Taenia taeniaeformis. Praziquantel is rapidly adsorbed via the surface of the parasites and acts primarily by changing the Ca++ permeability of the parasite membranes. This results in severe damage to the parasite integument, contraction and paralysis, disruption of metabolism and finally leads to the death of the parasite.
Emodepside is a semi-synthetic compound belonging to the new chemical group of depsipeptides. It is active against roundworms (ascarids and hookworms). In this veterinary medicinal product, emodepside is responsible for the efficacy against Toxocara cati, Toxascaris leonina, and Ancylostoma tubaeforme. It acts at the neuromuscular junction by stimulating presynaptic receptors belonging to the secretin receptor family which results in paralysis and death of the parasites.
Pharmacokinetics:
After topical application of an equivalent veterinary medicinal product to cats at the minimum therapeutic dose of 0.14 ml/kg bodyweight, mean maximum serum concentrations of 32.2 ± 23.9 μg emodepside/l and 61.3 ± 44.1 μg praziquantel/l were observed. Maximum concentrations were reached for 18.7 ± 47 hours after application for praziquantel and emodepside 3.2 ± 2.7 days. Both active substances are then slowly eliminated from the serum with a half-life of 4.1 ± 1.5 days for praziquantel and 9.2 ± 3.9 days for emodepside.
Studies in many different species show that praziquantel is rapidly metabolised in the liver. The main metabolites are monohydroxycyclohexyl derivatives of praziquantel. Renal elimination predominates. After oral application in the rat, emodepside is distributed to all organs. Highest concentration levels are found in the fat. Faecal excretion predominates with unchanged emodepside and hydroxylated derivatives as the major excretion products.