There are many types of medications available for heartworm prevention. What is the difference between the daily and monthly tablets?
answer Until the late 1980s, the only medication available for the prevention of heartworms had to be given daily. These products work by killing the microscopic heartworm larvae deposited by the mosquito, but must be given every single day to be most effective. This is because infective heartworm larvae quickly molt within two to three days into their fourth stage of development. This fourth stage can not be killed by the daily medication. Daily heartworm preventives have largely been replaced by monthly products and are no longer commercially available in the United States. Compounding pharmacies still formulate daily preventives on an “as needed” basis. An important note to keep in mind is that monthly medications are quickly eliminated from a pet’s system and do not continue to work for 30 days. Instead they work “backwards” to eliminate the larvae the pet acquired the previous 30 days, in essence, “de-heartworming” our pets each month in many cases, these monthly preventives contr
