Selamectin (trade names Revolution and Stronghold manufactured by Zoetis, and Revolt manufactured by Aurora Pharmaceuticals, among others) is a

topical A topical medication is a medication that is applied to a particular place on or in the body. Most often topical medication means application to body surfaces such as the skin or mucous membranes to treat ailments via a large range of class ...

parasiticide Antiparasitics are a class of medications which are indicated for the treatment of parasitic diseases, such as those caused by helminths, amoeba, ectoparasites, parasitic fungi, and protozoa, among others. Antiparasitics target the parasitic ag ...

and anthelminthic used on dogs and

cat The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of ...

s. It treats and prevents infections of

heartworms ''Dirofilaria immitis'', also known as heartworm or dog heartworm, is a parasitic roundworm that is a type of filarial worm, a small thread-like worm, that causes dirofilariasis. It is spread from host to host through the bites of mosquitoes. ...

flea Flea, the common name for the order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by ingesting the blood of their hosts. Adult fleas grow to about long, a ...

s, ear mites, sarcoptic mange (scabies), and certain types of

ticks Ticks (order Ixodida) are parasitic arachnids that are part of the mite superorder Parasitiformes. Adult ticks are approximately 3 to 5 mm in length depending on age, sex, species, and "fullness". Ticks are external parasites, living by ...

in dogs, and prevents heartworms, fleas, ear mites, hookworms, and roundworms in cats. It is structurally related to

ivermectin Ivermectin (, '' EYE-vər-MEK-tin'') is an antiparasitic drug. After its discovery in 1975, its first uses were in veterinary medicine to prevent and treat heartworm and acariasis. Approved for human use in 1987, today it is used to treat ...

and milbemycin. Selamectin is not approved for human use.

Usage

The drug is applied topically. It is

isopropyl alcohol Isopropyl alcohol (IUPAC name propan-2-ol and also called isopropanol or 2-propanol) is a colorless, flammable organic compound with a pungent alcoholic odor. As an isopropyl group linked to a hydroxyl group (chemical formula ) it is the simp ...

based, packaged according to its varying dosage sizes and applied once monthly. It is not

miscible Miscibility () is the property of two substances to mix in all proportions (that is, to fully dissolve in each other at any concentration), forming a homogeneous mixture (a solution). The term is most often applied to liquids but also appli ...

in water.

Mode of action

Selamectin disables

parasites Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

by activating

glutamate Glutamic acid (symbol Glu or E; the ionic form is known as glutamate) is an α-amino acid that is used by almost all living beings in the biosynthesis of proteins. It is a non-essential nutrient for humans, meaning that the human body can syn ...

-gated

chloride channels Chloride channels are a superfamily of poorly understood ion channels specific for chloride. These channels may conduct many different ions, but are named for chloride because its concentration ''in vivo'' is much higher than other anions. Several ...

muscle Skeletal muscles (commonly referred to as muscles) are Organ (biology), organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other ...

synapses In the nervous system, a synapse is a structure that permits a neuron (or nerve cell) to pass an electrical or chemical signal to another neuron or to the target effector cell. Synapses are essential to the transmission of nervous impulses from ...

. Selamectin activates the chloride channel without desensitization, allowing chloride ions to enter the nerve cells and causing neuromuscular

paralysis Paralysis (also known as plegia) is a loss of motor function in one or more muscles. Paralysis can also be accompanied by a loss of feeling (sensory loss) in the affected area if there is sensory damage. In the United States, roughly 1 in 5 ...

, impaired

muscular contraction Muscle contraction is the activation of tension-generating sites within muscle cells. In physiology, muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in muscle length, such as ...

, and eventual death. The substance fights both internal and surface parasitic

infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable d ...

. 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.

Side effects

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 medicine, a side effect is an effect, whether therapeutic or adverse, that is secondary to the one intended; although the term is predominantly employed to describe adverse effects, it can also apply to beneficial, but unintended, consequence ...

. 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.

Similar products

Main rival products for dogs include

(trade names ''Stromectol'', ''Ivermec'' and others) or

milbemycin oxime Milbemycin oxime, sold under the brand name Interceptor among others, is a veterinary medication from the group of milbemycins, used as a broad spectrum antiparasitic. It is active against worms (anthelmintic) and mites (miticide). Mechanism of ...

(''Interceptor'') for heartworms,

imidacloprid Imidacloprid is a systemic insecticide belonging to a class of chemicals called the neonicotinoids which act on the central nervous system of insects. The chemical works by interfering with the transmission of stimuli in the insect nervous system ...

and moxidectin (''Advocate''),

fipronil Fipronil is a broad-spectrum insecticide that belongs to the phenylpyrazole chemical family. Fipronil disrupts the insect central nervous system by blocking the ligand-gated ion channel of the GABAA receptor and glutamate-gated chloride (GluCl ...

(''Frontline'') or lufenuron (''Program'') for fleas, or the combination milbemycin oxime/lufenuron (''Sentinel'') for both.

References

External links

Pfizer Canada
Antiparasitic agents Macrolides Veterinary drugs Cat medications Dog medications Pfizer brands {{Endectocides