From Dog

Praziquantel (Droncit) is an anthelmintic wormer, commonly used in dogs for control of Dipylidium spp tapeworms.

It is also indicated for use in control of canine infections with Platynosomum spp, Opisthorchis felineus, Parametorchius complexus and Nanophyetus salmincola flukes.

The precise mechanism of action of praziquantel is unknown, but may involve synergy between praziquantel and the host's humoral immune response[1].

Praziquantel is rapidly taken up by helminths and also appears to increase permeability of helminth's cell membrane, leading to a loss of intracellular calcium. Massive contraction and paralysis of the helminth's musculature rapidly results. After exposure to praziquantel, integument in neck region of adult helminths develops blebs, which appear to burst and disintegrate[2]. Praziquantel also produces intense vacuolization at several sites in the integument of adult schistosomes. This is followed by phagocytic attachment to parasite and, ultimately, death[3].

Occasional side effects have been reported in a small percentage of cats, primarily anorexia, ptyalism and diarrhoea but appears to be temporary. Although anecdotal, praziquantel appears to be well tolerated in Queens but should be avoided in kittens under 8 weeks of age.


  1. Mandell GL, Douglas RG, Bennett JE (eds). Principles and practice of infectious diseases. 3rd ed. 1990. New York: Churchill Livingstone, pp 419-420
  2. Watt G, et al (1988) Praziquantel pharmacokinetics and side effects in Schistosoma japonicum-infected patients with liver disease. J Infect Dis 157(3):530-535
  3. Bindley PJ, Sher A. (1987) The chemotherapeutic effect of praziquantel against Schistosoma mansoni is dependent on host antibody response. J Immunol 139:215-220