Terbinafine hydrochloride (Lamisil) is an allylamine that inhibits squalene epoxidase, an enzyme involved in the synthesis of fungal cell walls. A patient receiving oral terbinafine hydrochloride for a dermatophyte infection is at risk for hepatotoxicity. The patient should be informed prior to initiating therapy and should be instructed to contact the clinician if adverse effects develop during therapy.


Types of hepatic damage that may develop during terbinafine therapy include:

(1) hepatocellular hepatitis

(2) cholestatic hepatitis

(3) mixed hepatocellular-cholestatic hepatitis

(4) autoimmune hepatitis

(5) fulminant necrosis


Risk factors for terbinafine-associated hepatotoxicity:

(1) pre-existing liver disease

(2) continued therapy after the appearance of liver dysfunction


It is recommended that a patient who is to be started on terbinafine for the treatment of onychomycosis should have fungal cultures performed on the nail to confirm the diagnosis prior to initiating therapy.


Clinical findings may include:

(1) malaise and/or fatigue

(2) jaundice

(3) pruritus

(4) anorexia

(5) right upper quadrant abdominal pain

(6) nausea and vomiting

(7) dark urine and/or pale stools


The onset of hepatotoxicity is usually 4 to 6 weeks after initiation of systemic therapy. Liver function tests should be performed before starting therapy, 4 to 6 weeks later and if the patient develops liver disease.


The liver disease usually resolves after the terbinafine is discontinued but It may take up to 2 years for a full recovery to occur.


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