Antifungal Drug Use for Onychomycosis

Abstract

Background: Onychomycoses are fungal nail infections affecting predominantly toenails, and mainly caused by dermatophyte fungi, molds and some Candida species. Nail infections can be mild with purely cosmetic implications, but they can also negatively influence quality of life. The deep-seated nature of fungi within the nail plate, prolonged treatment, poor patient adherence, frequent recurrences, and development of resistance to various antimicrobial agents make onychomycosis difficult to successfully treat. Areas of Uncertainty: When and how should clinicians prescribe systemic and topical antifungal drugs for onychomycosis? Data Sources: A narrative review was undertaken of the current literature identified in Medline, Scopus, CINAHL, the Cochrane library, and Google Scholar. Results: Treatment is often lengthy and requires persistence and patient education. Definitive mycological diagnosis, and an individualized evaluation of risks and benefits of different treatments are imperative before initiating therapy. The choice of treatment can be influenced by the age and general health of the patient, the causative organism, the number of affected nails, and the extent of nail involvement. Oral antifungals offer greater likelihood of a cure than topicals, but oral therapy carries greater risks and requires closer monitoring. Oral terbinafine is the treatment of choice, followed by itraconazole pulse regimen. The newly approved topical agents, efinaconazole and tavaborole, were superior to placebo in clinical trials and appear to produce slightly improved mycological cure rates compared to previous topicals, but further direct comparisons are needed. Conclusions: The treatment of onychomycosis can be challenging, as most therapeutic options are lengthy, expensive and potentially unsuccessful.

Onychomycosis: An Updated Review

“…The condition, if left untreated, may cause discomfort, pain, paresthesia, nail deformities such as transverse over-curvature, difficulties in trimming thick nail plates, difficulties in fitting shoes, and low self-esteem [ 7 , 9 , 14 , 37 , 53 , 78 , 89 ]. In addition, onychomycosis can be unsightly and socially embarrassing (especially for females) and may have an adverse affect on quality of life [ 4 , 6 , 7 , 90 - 92 ].…”

“…Currently, oral terbinafine (< 25kg, 125mg once daily; 25 to 35kg, 187.5mg once daily; > 35mg, 250mg once daily) is the drug of choice for the treatment of onychomycosis [ 39 , 53 , 62 , 88 , 100 , 101 ]. Adverse events include headaches, taste disturbance, dermatitis, anorexia, vomiting, epigastric pain, diarrhea, drug-to-drug interactions and, rarely, depression, neutropenia, hepatic dysfunction, and Steven-Johnson syndrome [ 4 , 17 , 53 , 81 ]. Generally, continuous terbinafine treatment has similar efficacy as pulse terbinafine treatment although some studies have shown superiority of continuous versus pulsed terbinafine treatment for toenail onychomycosis [ 102 ].…”

“…As such, concurrent nail polish use should be avoided. Commonly used topical antifungal agents include efinaconazole (Jublia, Clenafin) (10% nail solution), tavaborole (Kerydin) (5% nail solution), ciclopirox (Ciclodan, Penlac, Loprox) (8% nail lacquer or hydrolacquer), amorolfine (Curanail, Loceryl, Locetar, Odenil) (5% nail lacquer), and terbinafine (Lamisil) (10% nail solution) [ 4 , 6 , 43 , 53 , 106 , 109 , 110 ]. Generally, topical antifungal agents are well-tolerated; adverse events are minimal and include periungual erythema and burning at the application site [ 6 , 111 , 112 ].…”

“…Generally, topical antifungal agents are well-tolerated; adverse events are minimal and include periungual erythema and burning at the application site [ 6 , 111 , 112 ]. However, topical therapy requires longer treatment courses (often 48 weeks or longer) and may be less effective than oral treatment possibly because of insufficient nail plate penetration [ 4 , 14 , 88 ]. The impermeability of the nail can be attributed to the highly stable disulfide linkages and hydrogen bonds in the keratin network [ 105 ].…”

“…Any component of the nail unit, including the nail plate, nail matrix, and nail bed can be affected [ 3 ]. The term “onychomycosis” is derived from the Greek words “ onyx ” meaning nail and “ mykes ” meaning fungus [ 4 ]. Onychomycosis is the most common disorder affecting the nail unit and accounts for at least 50% of all nail diseases [ 2 , 5 , 6 ].…”