Terbinafine
Examples
Terbinafine
Indications
Dermatophyte infections of skin and nails
Contraindications
Contraindications
- Hypersensitivity to terbinafine
- Psoriasis
- Autoimmune disease (risk of lupus-erythematous-like effect)
- Hepatic impairment
- Renal impairment
- Pregnancy and breast-feeding
Mechanism
Selective inhibition the enzyme squalene epoxidase, which is involved in the synthesis of ergosterol from squalene in the fungal cell wall. The accumulation of squalene within the cell is toxic to the organism.
Administration
Oral, topical
Adverse Reactions
Not problematic with topical use.
Systemic use can cause:
Systemic use can cause:
- Abdominal discomfort, anorexia, nausea, diarrhoea
- Rash and urticaria, occasionally with arthralgia or myalgia
- Occasionally, taste disturbance
- Rarely liver toxicity (discontinue)
- Very rarely psychiatric disturbance, blood disorders and lupus like effects
Interactions
Antibacterials - rifampicin reduces plasma concentration of terbinafine
AmitriptyllineAmitriptyline- Terbinafine is predicted to increase exposure to amitriptyline.
Tamoxifen- Terbinafine is predicted to decrease the efficacy of tamoxifen.
Tramadol- Terbinafine is predicted to decrease the efficacy of tramadol.
Citalopram – Terbinafine is predicted to increase the exposure to citalopram.
Education
Patients should be warned that treatment can be needed for many weeks.
Pharmacokinetics
Terbinafine is rapidly absorbed and is taken up by skin, nails and adipose tissue. Given topically, it penetrates skin and mucous membranes. It is metabolised in the liver by the cytochrome P450 system, and the metabolites are excreted in the urine.
