Selamectin / Revolution

(selamectin)

Brand

Revolution, Stronghold

Availability

Topical liquid: 15 mg tubes of 0.25mL volume with a 60 mg/mL strength: mauve packaging labeled for use in kittens.
Topical liquid: 45 mg tubes of 0.75mL volume with a 60 mg/mL strength: blue packaging labeled for use in cats.

*Note: kitten and cat doses contain the same concentration just different amounts per tube. Either can be used. ²¹

Caution: packaging for Dogs is not the same as cats and kittens. Dog dosages contain a higher potency of 120 mg/mL.

Pharmacology

Selamectin is a semisynthetic; macrocyclic lactone anthelmintic obtained from fermentation extracts of the soil microorganism Streptomyces avermitilis. This topical drug is a member of the avermectin class of insecticides. It is a monosaccharide oxime derivative of doramectin, and structurally related to ivermectin.

Selamectin facilitates the release of GABA (gamma amino butyric acid) an inhibitory neurotransmitter and binds to glutamate-gated chloride channels in nerve and muscle cells of invertebrates. This specificity of action targets intestinal nematodes and arthropods (e.g., mites, fleas, lice) to a much greater degree than the mammals it is being applied to.

Mammals have a blood-brain barrier that prevents microscopic objects and large molecules such as toxins and many types of drugs from getting into and accumulating in the brain.
P-glycoprotein, which is known as multi-drug resistance gene MDR1, is a gate keeper for the blood brain barrier and highly restricts the entry of many drugs or toxins (e.g., selamectin or similar avermectins). In those animals having a homozygous MDR1 mutation these substances can accumulate in the brain and cause clinical signs of neurotoxicosis. Because selamectin is believed to be transported differently by P-glycoprotein across the blood brain barrier, allowing for less accumulation, it has been shown to have a higher therapeutic margin of safety than does ivermectin or doramectin. Even in the absence of P-glycoprotein, selamectin has been shown to accumulate to a much lesser degree.
However, it is important to keep in mind that young developing animals have a permeable blood brain barrier which can be more susceptible to the toxic effects of these substances than in adult animals.

Selamectin is readily absorbed through the skin. It is distributed via blood and concentrated in sebaceous glands to produce extended protection time from external parasites. It is also secreted into the intestines making it an endectocide for nematodes.

Selamectin is metabolized in the liver and is mostly excreted in feces with a lesser amount of excretion in urine.

Indications

Used to rid nematodes, mites (thought to be effective against demodectic mange mites), fleas, and lice.

Drug Interactions or Contraindications

Avoid concomitant use with barbiturates, benzodiazepines (e.g., Valium), and valproic acid in order to avoid increased sedation.
*Note: supported recommendation of Vanessa Pisano DVM. ²¹:

“Do not use Selamectin / Revolution on sick or malnutritioned rats, or on rats that are under 5 weeks old. For smaller sized rats greater than 5 weeks and under 4 months reduce dosage by half.”*

Adverse Reactions

Side effects or reactions are listed below, though noted to be uncommon.

CNS: tremors

Skin: irritation at site of application.

Dosage Recommendations

In general, a single topical application of selamectin (Revolution) provides a safe and effective treatment for ectoparasites.
*Note: The rat should be checked after two weeks for any evidence of continued infestation. In some instances, a second treatment (following a 30 day interval) may be needed. Rarely, and only by veterinary assessment, may it become necessary to dose at a two week interval.

Selamectin Topical Application: (mauve packet labeled for kittens, concentration listed above under Availability)
6 mg/kg once per month ⁴

or

Selamectin Topical Application: (mauve packet labeled for kittens, concentration listed above under Availability)
4 mg/kg to 8 mg/kg once per month or up to once every two weeks based on veterinary assessment. ¹²

or

6 mg/kg to 15 mg/kg, Spot On (topical), monthly. ⁴²

or

10 mg/kg to 12.4 mg/kg once (rats/mice) ⁴⁴

or

15 mg/kg, Spot On (topical). May be used for fleas and lice. ³⁵ May repeat in 10 days if advised by veterinarian.

or

15 mg/kg to 30 mg/kg topically q21 to 28 days times 2 treatments (q14 days if Demodex) ³⁴, ⁴¹^, ⁴⁴
*Note: higher dosing should be based on type and severity of infestation and under direction of a veterinarian only.

or

The following dosage recommendation and application information is contributed by Vanessa Pisano, DVM; VC North Springs, FL. ²¹:

Selamectin Topical Application: (blue packet labeled for cats, concentration listed above under Availability)
0.02 mL for rat weighing less than 1 pound. For a larger rat greater than 1 pound, 0.05 mL.
Apply once per month or up to once every two weeks based on veterinary assessment.

To Administer:
Push cap down on tube to puncture the seal and squeeze tube till a tiny bead is on the tip of tube or draw up the amount needed for application in a needleless tuberculin syringe.
Part the rat’s fur at the base of the neck behind the head (an area difficult for the rat to clean off) and either touch the tube with the tiny bead of liquid to the skin or apply with a needleless syringe.
Do not massage liquid into skin. Allow the area to dry before returning the rat to his cage.
If too much liquid is accidentally applied, wash the rat immediately and wait 2 weeks before reapplying. ²¹
*Note: product contains alcohol. Do not apply to broken areas of skin.

Considerations

No reports on use in pregnant or lactating rats, wise to consider the following as seen in the monograph for ivermectin. Always consult a veterinarian if choosing to use in pregnant and lactating rats. Dose the mother rat at the recommended adult rat dose. Baby rats should not be given separate treatment since dosing would be achieved through nursing from mother rat.
Topical application of selamectin recommended less stressful to rats than the use of injectable medications.
Do not apply immediately after bathing. Allow skin and fur to dry before application.
*Note for humans: rare instances of reactions such as eye irritation, hives, itching, and skin redness have been reported in humans having frequent contact with, and hypersensitivity to, Revolution. Wash hands with soap and water immediately after skin contact with product. If eye contact, flush the eyes copiously with water.
Store at semi-cool room temperature and protect from light.

References

Freedom of Information Summary: Revolution™ (selamectin). (2000, June 13). Retrieved December 15, 2008, from https://www.fda.gov/OHRMS/DOCKETS/98fr/141152fs.pdf.
Fisher, M., Beck, W., & Hutchinson, M. (2007). Efficacy and Safety of Selamectin (Stronghold®/Revolution™) Used Off-Label in Exotic Pets. The International Journal of Applied Research in Veterinary Medicine, 5(3), 87-96. Retrieved February 3, 2011, from http://www.jarvm.com/articles/Vol5Iss3/Beck%2087-96.pdf
Geyer, J., Gavrilova, O., & Petzinger, E. (2009). Brain penetration of ivermectin and selamectin in mdr1a,b P-glycoprotein- and bcrp- deficient knockout mice. Journal of Veterinary Pharmacology and Therapeutics, 32(1), 87-96. doi:10.1111/j.1365-2885.2008.01007.x
Woodward, K. (2013). Toxicological effects of veterinary medicinal products in humans (Vol. 1). Cambridge: Royal Society of Chemistry.