Benzyl benzoate:Uses, Mechanism of action, Side effects and Toxicity

Benzyl benzoate is an active substance in Peruvian and Tulu balsams as well as other essential oils. It is also produced synthetically and is formulated as a liquid, emulsion, or lotion.

Uses

Benzyl benzoate can be made in a 10–25% solution for the topical treatment of scabies. Although there are no commercially available preparations, it is often compounded into a solution. There are few published human studies on its use for scabies, but it is commonly used in many countries outside the United States, where it is reported to be a very inexpensive and effective compound. One study found that 15% benzyl benzoate applied twice daily for 3 days, used in combination with a single dose of ivermectin, was an extremely effective scabies treatment in an HIV-positive population.[1]

Mechanism of action

Benzyl benzoate exerts toxic effects on the nervous system of the parasite, resulting in its death. It is also toxic to mite ova, though its exact mechanism of action is unknown. In vitro, benzyl benzoate has been found to kill the Sarcoptes mite within 5 minutes.

Side effects

Benzyl benzoate has low acute toxicity in laboratory animals. It is rapidly hydrolyzed to benzoic acid and benzyl alcohol. Benzyl alcohol is subsequently metabolized to benzoic acid. The conjugates of benzoic acid (hippuric acid and the glucuronide of benzoic acid) are rapidly eliminated in urine. When given in large doses to laboratory animals, benzyl benzoate can cause hyperexcitation, loss of coordination, ataxia, convulsions, and respiratory paralysis.

Benzyl benzoate can be a skin irritant when used as a topical scabicide. Overdose can result in blistering and hives or a rash can occur as an allergic reaction.

As an excipient in some testosterone-replacement injectable medications, benzyl benzoate has been reported as a cause of anaphylaxis in a case in Australia.

Toxicity

Oral, rabbit: LD50 = 1680 mg/kg; Skin, rabbit: LD50 = 4000 mg/kg. Symptoms of overdose include blister formation, crusting, itching, oozing, reddening, or scaling of skin; difficulty in urinating (dribbling); jerking movements; sudden loss of consciousness.

References

[1] Shiva S. Krishnan, Benjamin N. Lockshin, 39 - Topical antiparasitic agents, 2013, Pages 481-486.e1, ISBN 9781437720037, https://doi.org/10.1016/B978-1-4377-2003-7.00039-X.