About 6 weeks after treatment the dog is treated to eliminate circulating mfs. Ivermectin or milbemycin are highly effective. Place the dog or cat in a heartworm preventive program unless there are large numbers of mfs. Because of possible toxic reactions to treatment, animals should be carefully monitored after treatment and appropriate support and care provided. The efficacy of treatment can be determined by another test for the presence of mfs.

The owner must understand the risk that treatment imposes on the dog.