Selamectin

Selamectin is applied topically. It is not miscible in water.

Selamectin disables parasites by activating glutamate-gated chloride channels at muscle synapses. Selamectin activates the chloride channel without desensitization, allowing chloride ions to enter the nerve cells and causing neuromuscular paralysis, impaired muscular contraction, and eventual death.

The substance fights both internal and surface parasitic infection. Absorbed into the body through the skin and hair follicles, it travels through the bloodstream, intestines, and sebaceous glands; parasites ingest the drug when they feed on the animal's blood or secretions.

Selamectin has been found to be safe and effective in a 2003 review.

Selamectin has high safety ratings, with less than 1% of pets displaying side effects. In cases where side-effects do occur, they most often include passing irritation or hair loss at the application site. Symptoms beyond these (such as drooling, rapid breathing, lack of coordination, vomiting, or diarrhea) could be due to shock as a result of selamectin killing heartworms or other vulnerable parasites present at high levels in the bloodstreams of dogs. This would be a reaction due to undetected or underestimated infections prior to using the medication, rather than an actual allergic reaction to the drug itself.

Brand names

Selamectin is sold under various brand names including Selehold, manufactured by KRKA, Selarid manufactured by Norbrook Laboratories Limited, Revolution and Stronghold manufactured by Zoetis, Revolt manufactured by Aurora Pharmaceuticals, and Senergy manufactured by Virbac.

Similar products

Main rival products for dogs include ivermectin (trade names Stromectol, Ivermec and others) or milbemycin oxime (Interceptor) for heartworms, imidacloprid and moxidectin (Advocate), fipronil (Frontline) or lufenuron (Program) for fleas, or the combination milbemycin oxime/lufenuron (Sentinel) for both.