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INDEX |
| Introduction | Terbinafine is a synthetic allylamine discovered and manufactured by Novartis. Clinical studies commenced in the late 1980's and the drug was licensed in 1992. It is now the leading compound for fungal nail infections. | |
| Dose & Delivery | Terbinafine is only available orally and topically. | |
| Fungi - the drug is active against. | Terbinafine is active against all the skin fungi, including Epidermophyton floccosum, Microsporum species and Trichophyton species. It is also active against Malassezia furfur which causes pityriasis tinea (versicolor). It is active against most Candida species, athough it may not be fungicidal in some species such as Candida albicans. This is little activity demonstrated against Aspergillus. It has limited activity against other organisms. | |
| Typical regimens. |
The typical dose is 250mg per day. This should
be reduced in those with impaired liver or renal
function. Significant skin infections are
treated for 3-4 weeks. Nail infections of the
fingers require at least 6 weeks of treatment,
but toenails require 6 months of therapy. In
the treatment of athletes foot, terbinafine
cream can be applied between the toes daily for
7 days. Experimental indications for terbinafine include aspergillosis and resistant Candida infections Larger doses have been used for these conditions. |
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| Metabolism distribution and excretion. | Terbinafine is well absorbed when taken orally. There is no effect of food on absorption. As it is a fat soluble drug it accumulates in skin, fatty tissue and also the nails. It persists in nails for long periods after the end of treatment. It is metabolised by the liver with a the half life of 17 hours. This is prolonged in patients with liver or kidney impairment. | |
| Drug/Drug interactions | Terbinafine has the advantage over the azoles in not affecting the metabolism of such drugs as cyclosporin and oral diabetic drugs. Its blood levels are reduced if given with rifampicin (rifampin) as this increases the rate of metabolism. Cimetidine, the anti ulcer drug also inhibits its metabolism, so higher blood levels are found if the drugs are given together. | |
| Side effects | Terbinafine is well tolerated, its common side effects are nausea, mild abdominal discomfort, allergic skin reactions have been reported, although these are uncommon. Loss of taste or altered taste is also reported. Rarely has liver dysfunction been reported. | |
| Other information |