By Gary M. White, MD
The complete package insert should be consulted before prescribing. Key points are as follows.
Onychomycosis due to dermatophytes.
Topical terbinafine comes as a cream, spray and a spray powder. It is applied once daily. It may be used till all signs and symptoms are gone and then for 2-3 more days.
Terbinafine 250 mg PO QDay for 12 weeks for toenails and 6 weeks for fingernail onychomycosis
Baseline liver function testing should be performed. Periodic monitoring of liver function tests is recommended. In patients with known or suspected immunodeficiency, physicians should consider monitoring complete blood counts if treatment continues for more than 6 weeks.
Exact recommendations are lacking, but it seems reasonable to obtain a baseline CBC and SGPT and repeat the same in 3-4 weeks. The risk of idiosyncratic hepatobiliary dysfunction has been estimated at about 1:50,000.
Cases of liver failure, some leading to liver transplant or death, have occurred with the use of terbinafine in individuals with and without preexisting liver disease. In the majority of liver cases, the patients had serious underlying systemic conditions. The severity of hepatic events and/or their outcome may be worse in patients with active or chronic liver disease. Treatment with Lamisil Tablets should be discontinued if biochemical or clinical evidence of liver injury develops.
Lamisil Tablets are not recommended for patients with chronic or active liver disease. Thus, baseline labs are required.
GI symptoms (e.g. GI irritation, stomach pain, dyspepsia, nausea, vomiting and diarrhea) are most common and occur in approximately 5%.
Alterations in taste (e.g. diminished taste, lose of taste, metallic taste) may occur and reverses after the drug is stopped. For example, it may take 4-6 weeks to return after stopping therapy. Discoloration of the tongue and alterations in smell have also been reported.
Neutropenia and pancytopenia has also been reported. In several cases, the neutropenia had its onset about 30 days after starting the medication [BJD 1999;140;1196].
Skin eruptions (e.g. exanthematous eruption, urticaria, pruritus, eczema and erythroderma, an erythema annulare centrifigum-like psoriatic drug eruption, SJS, and TEN) develop in 2.7% of patients. Renal impairment has been reported in one patient [BJD 1996;134;374]. A lupus like eruption with a photosensitive rash and positive ANA has been reported [Cutis 1999;64;56]. Acute generalized exanthematous pustulosis has developed in several patients [JDT 1999;10;283].
The development of a greenish hue of non-green objects has been reported (AD 1996;132;846). Aka dyschromatopsia.
Category B, but since the treatment of onychomycosis can usually be postponed, terbinafine should not be given during pregnancy.