Safe Use of Ivermectin – Doses of Ivermectin in Dogs | petMD -- Heartworm preventive for $15.00 per year. I use Ivermectin to treat my dog for heartworm. I grew up on a farm and we've always vetted our own animals. This is the drug we used to treat our cattle for the same parasite. This article explains the proper dosage for dogs and which dogs maybe shouldn't be treated with straight Ivermectin.