VetriShield Max is a prescription, parasite preventative for dogs that protects against heartworm disease and intestinal worms. It kills heartworm larvae and treats hookworm, tapeworm, and roundworm infections. VetriShield Max is a flavored, chewable tablet that contains the anti-parasitic medications ivermectin, pyrantel, praziquantel. It provides 30 days of parasite protection for your dog. This medication is for use in dogs eight weeks of age and older.