Adult: 250 mg once daily for 6 weeks (fingernail) or 12 weeks (toenail).
Topical/Cutaneous Tinea pedis
Adult: As 1% cream: Apply to affected area 1-2 times daily for 1 week (between toes) or 2 weeks (bottom or sides of feet). As spray: Spray between the toes bid for 1 week. As gel: Apply to affected area once daily for 1 week. Child: ≥12 years As cream or spray: Same as adult dose. Dosage recommendations may vary among countries or individual products. Refer to country- or product-specific recommendations.
Adult: As 1% cream: Apply 1-2 times daily for 2 weeks.
Topical/Cutaneous Tinea corporis, Tinea cruris
Adult: As 1% cream: Apply to affected area 1-2 times daily for 1-2 weeks. As 1% gel or spray: Apply to affected area once daily for 1 week. Child: ≥12 years As 1% cream or spray: Same as adult dose. Dosage recommendations may vary among countries or individual products. Refer to country- or product-specific recommendations.
Renal Impairment
Administration
May be taken with or without food.
Contraindications
Hypersensitivity. Chronic or active liver disease. Lactation.
Perform LFT before treatment and periodically (after 4-6 weeks of treatment). Monitor CBC for therapy >6 weeks in immunosuppressed patients.
Overdosage
Symptoms: Headache, nausea, vomiting, epigastric pain, rash, frequent urination, and dizziness. Management: Symptomatic and supportive treatment. May administer activated charcoal to adsorb and eliminate the drug.
Drug Interactions
Increased effect or plasma concentration with CYP2C9 and CYP3A4 inhibitors (e.g. cimetidine, fluconazole, amiodarone). Decreased effect or plasma concentration with rifampicin. Terbinafine increases the effect of TCAs (e.g. desipramine), beta-blockers (e.g. atenolol), SSRIs (e.g. escitalopram), MAOIs (e.g. rasagiline) by inhibiting CYP2D6 enzyme. Decreases the clearance of caffeine. Increases the clearance of ciclosporin.
Action
Description: Terbinafine is a synthetic allylamine derivative that interferes with fungal sterol biosynthesis by inhibiting squalene epoxidase. This results in a deficiency in ergosterol and intracellular accumulation of squalene within the fungal cell membrane, leading to fungal cell death. Pharmacokinetics: Absorption: Well absorbed from the gastrointestinal tract (>70%). Bioavailability: Approx 40%. Time to peak plasma concentration: Within 2 hours. Distribution: Distributed mainly to stratum corneum, sebum, hair, and nail matrix, bed, and plate. Enters breast milk. Plasma protein binding: >99%. Metabolism: Rapidly and extensively metabolised in the liver mainly by CYP1A2, CYP3A4, CYP2C8, CYP2C9, and CYP2C19 to inactive metabolites. Undergoes first-pass metabolism. Excretion: Mainly via urine (80%, as inactive metabolites); faeces (20%). Plasma elimination half-life: 200-400 hours (terminal); approx 36 hours (effective).
Chemical Structure
Terbinafine Source: National Center for Biotechnology Information. PubChem Database. Terbinafine, CID=1549008, https://pubchem.ncbi.nlm.nih.gov/compound/Terbinafine (accessed on Jan. 23, 2020)
D01AE15 - terbinafine ; Belongs to the class of other antifungals for topical use. D01BA02 - terbinafine ; Belongs to the class of antifungals for systemic use.
References
Anon. Terbinafine (Systemic). AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 22/04/2021.Anon. Terbinafine (Systemic). Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 22/04/2021.Anon. Terbinafine (Topical). AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 22/04/2021.Anon. Terbinafine (Topical). Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 22/04/2021.Buckingham R (ed). Terbinafine. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 22/04/2021.Dr Reddy’s New Zealand Ltd. Terbinafine-DRLA Tablets data sheet 2 June 2017. Medsafe. http://www.medsafe.govt.nz. Accessed 22/04/2021.Joint Formulary Committee. Terbinafine. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 22/04/2021.Lamisil Aerosol Spray (GlaxoSmithKline Consumer Healthcare Holdings US LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 22/04/2021.Lamisil AT 1% Gel (GlaxoSmithKline Consumer Healthcare UK Trading Limited). MHRA. https://products.mhra.gov.uk. Accessed 03/05/2021.Nafine Cream (Prime Pharmaceutical Sdn. Bhd.). National Pharmaceutical Regulatory Agency - Ministry of Health Malaysia. https://www.npra.gov.my. Accessed 22/04/2021.Terbinafine 250 mg Tablets (Dr Reddy’s Laboratories UK Ltd). MHRA. https://products.mhra.gov.uk. Accessed 22/04/2021.Terbinafine Hydrochloride 1% Cream (Gedeon Richter Plc.). MHRA. https://products.mhra.gov.uk. Accessed 22/04/2021.Terbinafine Hydrochloride Cream (Pharmacy Value Alliance LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 22/04/2021.Terbinafine Hydrochloride Tablet (Breckenridge Pharmaceutical, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 22/04/2021.