Heartworm is a potentially deadly parasite that can be very hard to treat once established, but fortunately preventing heartworm can be as simple as administering a monthly tablet to your pet.

Two popular treatments are Sentinel Flavor Tabs - for dogs only - and Interceptor tablets, which are available for both dogs and cats. These work to prevent heartworm from developing, and also control intestinal parasites including hookworms, roundworms, and whipworms.

Both of these tablets work by using the same active ingredient, Milbemycin Oxime. Sentinel Flavor Tabs contain an additional ingredient (Lufenuron) that helps to control flea infestations. It works by preventing any flea eggs from developing but does not kill existing adult fleas.

Sentinel and Interceptor may be given to dogs and puppies as young as 4 weeks old, and are safe for use with pregnant or nursing dogs.

Interceptor is only suitable for cats and kittens over 6 weeks of age and is not tested as safe for pregnant, nursing or breeding cats.

Top tip: Once pets develop heartworm it can be very hard to treat, so prevention is always better than cure. Compare the major brands of heartworm preventatives.