By Angela Pollock

Interceptor for dogs is a prescription medication used to prevent a host of internal parasites. According to the manufacturer, Interceptor “prevents heartworm disease, controls adult hookworm, and removes and controls adult roundworm and whipworm infections in dogs and puppies.” Like with most all medications, this product can have side effects especially when not used correctly.

Interceptor is a popular heartworm preventative by people who own Collies. Although the debate is still ongoing, some feel that the active ingredient ivermectin can be dangerous to Collie breeds thus Collie owners avoid heartworm preventatives that contain ivermectin.  The Collie Club of America discusses toxicity of ivermectin in Collies but other experts report that it is safe for this specific breed. Owners that do not want to take chances with their pet’s health, opt for Interceptor because it does not contain ivermectin.

This heartworm preventative is available in tablet form which is given to a dog once a month. The pills come in four different colors that have different dosages of the active ingredient Milbemycin oxime. Brown is the lowest dosage with 2.3 mg and white has the most with 23.0 mg. Also available are green tables (5.75 mg) and yellow (11.5 mg).

Interceptor dosages
The recommended dosage by the product manufacturer is 0.23 mg per each pound the dog weighs. To break this down, small dogs weighing on average 2-10 pounds are given the lowest dosage or a brown tablet, dogs 11-25 pounds get green, 26-50 pound dogs get yellow, and the heaviest dogs weighing 51-100 pounds are prescribed the white tablets. Dogs that weigh over 100 pounds may receive a combination of tablets in order to receive the correct dosage.

Side effects of Interceptor
The side effects of interceptor in dogs have ranged from mild to severe. The mildest of side effects reported include weakness, depression and/or lethargy. Severe side effects have included vomiting, diarrhea, ataxia, anorexia, and convulsions.

Interceptor precautions
Interceptor was not designed for puppies less than four weeks of age and any dog that weighs less than two pounds. All dogs should be tested for heartworm disease prior to taking any heartworm preventative regardless of the brand. 

Heartworm disease in dogs
Heartworm disease is a preventable fatal disease that affects thousands of dogs every year. The disease is transmitted from animal to animal via mosquitoes. The mosquitoes infect dogs with larvae that can mature into adult worms that reach over a foot long. The worms attack the heart by damaging the blood vessels leading to lung and heart disease. 

Interceptor tablets for dogs are generally given with meals. Dogs that do not have problems taking medicine can simply be fed the pill. A dog should be monitored when given the tablet to insure the dog has ingested the entire medication. In the United States, Interceptor can only be legally obtained with a prescription from a licensed veterinarian.