Manufacturer: Mavlab Pty Ltd Composition Ivermectin 136 microgram. Actions Ivermectin kills heartworm larvae acquired within the previous 30 days. May be given to stud dogs and pregnant bitches. Indications Prevention of heartworm in dogs. Contraindications Administration to puppies under 6 weeks of age. Dosage and Administration Dogs < 12 kg. ½ a chewable monthly. Dogs 12 to 22 kg. 1 chewable monthly. Dogs > 22 kg. 2 chewables monthly.