Efficacy of a drug combination of praziquantel, pyrantel pamoate, and febantel against giardiasis in dogs.

To evaluate efficacy of a combination of praziquantel, pyrantel pamoate, and febantel at 2 dosages for treating naturally acquired giardiasis in dogs. 6 male and 9 female Beagles. Dogs were identified as naturally infected with Giardia sp, using the zinc sulfate concentration technique (ZSCT), and were allocated to 1 of 3 groups. Group-1 dogs were treated orally with a praziquantel (5.4 to 7 mg/kg of body weight), pyrantel pamoate (26.8 to 35.2 mg/kg), and febantel (26.8 to 35.2 mg/kg) combination, every 24 hours for 3 doses. Group-2 dogs were treated with the combination once. Group-3 dogs were nontreated controls. Four fecal samples were examined, using the ZSCT, from each dog of each group within 6 days of the last treatment. Dogs were considered to have giardiasis if 1 or more of the fecal samples had positive results for Giardia cysts. Dogs were examined daily for at least 10 days after the last treatment. Giardia cysts were not detected in the feces of any group-1 dog or in the feces of 2 of 5 group-2 dogs. Cysts were detected in the feces of 5 of 5 group-3 (nontreated control) dogs. Signs of toxicosis were not observed in any dog. The current labeled dose (for treatment of various nematodes and cestodes, but not Giardia sp) of the combination given orally once reduces cyst excretion in Giardia-infected dogs, and should be considered for treatment of dogs shedding Giardia cysts, whether or not they have clinical signs of infection.