Tavaborole

Tavaborole is a synthetic antifungal agent of the oxaborole class, used topically to treat onychomycosis of the toenail caused by dermatophyte fungi. It is a boron-containing compound that was developed for topical use and is marketed as a 5% topical solution under the brand name Kerydin.

Mechanism of action: Tavaborole inhibits fungal protein synthesis by targeting leucyl-tRNA synthetase (LeuRS). It binds to the editing site of LeuRS and forms a stable adduct with tRNA, blocking aminoacylation and thereby slowing fungal growth. The effect is generally fungistatic rather than fungicidal.

Indications and administration: Tavaborole is indicated for onychomycosis of the toenail caused by dermatophyte fungi. The recommended regimen is once daily application to the affected nail and surrounding skin for 48 weeks. Efficacy for non-dermatophyte molds or Candida species has not been established.

Pharmacokinetics and interactions: Systemic absorption after topical application is minimal, resulting in low systemic exposure. Because of the limited systemic presence, clinically significant drug interactions are unlikely.

Safety and adverse effects: The most common adverse events are local application-site reactions, including dermatitis, erythema, pruritus, and nail bed irritation. Serious systemic adverse events are rare. Patients should avoid contact with eyes and mucous membranes; data in pregnancy are limited and use should be guided by clinical judgement.

History: Tavaborole was developed by Anacor Pharmaceuticals and approved by the U.S. FDA in 2014 for toenail onychomycosis. The company was later acquired by Pfizer.