Treatment of heartworms is still somewhat risky, but it is much safer today than it was years ago, when treatment involved the use of a medication containing arsenic which had many severe side effects, including liver failure and death. Now there is a much safer medicine, melarsomine dihydrochloride, which kills adult and immature heartworms and does not have as many side effects as the previous medicine. However, there is still some risk involved: lethargy, lack of appetite, saliva, increased heart rate, and retching can occur with this new drug.
Before determining the treatment plan, the veterinarian first will perform a variety of tests to determine the severity of the disease, including x-rays, bloodwork, and a urinalysis. Sometimes, an electrocardiogram and an echocardiogram are recommended to assess more accurately the condition of the heart.
Generally, the melarsomine dihydrochloride will be administered as two deep muscle injections, given 24 hours apart. The dog is kept hospitalized and monitored closely for any reactions. If the disease is staged as severe, however, the veterinarian will alter the treatment plan to minimize the potential side effects. Three to four weeks after the injections are given, a medication will be administered to kill the circulating microfilaria. The dog must rest during this entire period to prevent adverse effects from occurring. No running, jumping, or excessive stair climbing should be allowed. Owners should walk their dogs slowly on a leash.
