Selamectin (Revolution) was introduced in 1999 by Pfizer Animal Health. It is a semi-synthetic avermectin derived from a bioengineered strain of Streptomyces avermitilis. Selamectin binds to receptors on glutamate-gated (and possibly GABA-gated) chloride channels, leading to flaccid paralysis and death of parasites.
Selamectin's greater affinity for insect chloride channels accounts for its safety in animals, especially collie breeds. Selamectin is a topical spot-on formulation that is absorbed through the skin into the blood and then is redistributed to the sebaceous glands. Selamectin achieves 100 percent flea kill by 24 hours after application, however, by 28 days after application, flea kill has decreased significantly.
In dogs, selamectin is labeled for control of flea infestations, prevention of heartworm disease (D. immitis), control of ear mites (O. cynotis) and control of internal parasites. This drug has also been used for control of Cheyletiella spp when used monthly for 3 months. Control of Notoedres spp has also been reported when used fortnightly for three applications.
Selamectin can be used in puppies from 6 weeks of age, and is safe for breeding, pregnant and lactating bitches.
Adverse reactions are infrequent, although local irritation and anecdotal reports of local alopecia are not infrequent. Rare instances of vomiting, loose stools, anorexia, lethargy, tachypnoea and muscle tremors also have been reported.
- Schwassman, M & Logas, D (2010) How to treat common parasites safely. In August, JR (Ed): Consultations in feline internal medicine. Vol 6. Elsevier Saunders, Philadelphia. pp:390