Use with caution in sick, debilitated, or underweight animals and dogs weighing less than 10 lbs (see Animal Safety). The safe use of this drug has not been evaluated in pregnant or lactating bitches.
All dogs should be tested for existing heartworm infection before starting treatment with QuadriGuard™, which is not effective against adult D. immitis. Infected dogs should be treated to remove adult heartworms and microfilariae before initiating a heartworm prevention program.
While some microfilariae may be killed by the ivermectin in QuadriGuard™ at the recommended dose level, QuadriGuard™ is not effective for microfilariae clearance. A mild hypersensitivity-type reaction, presumably due to dead or dying microfilariae and particularly involving a transient diarrhea, has been observed in clinical trials with ivermectin alone after treatment of some dogs that have circulating microfilariae.