Terbinafine

Oral
Dermatophytosis

Topical/Cutaneous
Dermatophytosis

CrCl (mL/min)	Dosage
<50	Reduce to 50% of usual dose.

May be taken with or without food.

Hypersensitivity. Chronic or active hepatic disease. Lactation.

Patient w/ immunosuppression, psoriasis, autoimmune disease (e.g. Lupus erythematosus); presence of lesion (topical). Renal impairment (CrCl <50 mL/min). Pregnancy.

Significant: Depression, taste and smell disturbances, wt loss, anxiety. Rarely, SLE; psoriasis exacerbation; ocular lens and retina changes; blood disorders (e.g. decreased lymphocyte count, neutropenia, agranulocytosis, pancytopenia).
Nervous: Headache.
GI: Dyspepsia, nausea, vomiting, diarrhoea, abdominal distention/pain, toothache, pharyngolaryngeal pain, decreased appetite, feeling of fullness.
Resp: Influenza, nasopharygitis, upper resp tract infections, nasal congestion, rhinorrhea.
Musculoskeletal: Arthralgia, myalgia.
Ophthalmologic: Vision color changes, color confusion, decreased visual acuity.
Dermatologic: Rash, pruritus, urticaria, skin exfoliation.
Others: Fever, application site reactions (e.g. pain/irritation pigmentation disorder, burning sensation).
Potentially Fatal: Hepatic failure. Rarely, serious skin and hypersensitivity reaction (e.g. Stevens-Johnson syndrome, toxic epidermal necrolysis, erythema multiforme, exfoliative dermatitis, bullous dermatitis, drug reaction w/ eosinophilia and systemic symptoms [DRESS] syndrome); thrombotic microangiopathy (e.g. thrombocytopenic purpura, haemolytic uraemic syndrome).

PO/Topical: B

Avoid contact w/ eyes.

Perform LFT before initiation of oral therapy and monitor 4-6 wk thereafter. Monitor CBC for therapy >6 wk.

Symptoms: headache, nausea, upper abdominal pain, and dizziness. Management: Symptomatic and supportive treatment. Administer activated charcoal w/in 1-2 hr after ingestion orally or via nasogastric tube for unconscious patient.

Increased serum concentration w/ cimetidine, CYP450 inhibitors (e.g. fluconazole, amiodarone, ketoconazole). Decreased serum concentration w/ rifampicin. May increase plasma concentration of TCA(s), β-blockers, SSRIs, antiarrythmics, MAOI(s) type B. May cause menstrual disturbances (e.g. breakthrough bleeding, irregular cycle) w/ OC. May decrease clearance of despiramine.

Description: Terbinafine is a allylamine derivative that has a wide spectrum of antifungal activity against pathogens of the skin, hair, and nails. It acts by inhibiting squalene epoxidase, the main enzyme responsible for fungal sterol synthesis. Thus, resulting to ergosterol deficiency, leading to membrane disruption and cell death. It is active against dermatophytes, moulds, and certain dimorphic fungi.
Pharmacokinetics:
Absorption: Well absorbed from the GI tract. Minimal absorption through the skin. Bioavailability: 40%. Time to peak plasma concentration: W/in 2 hr (oral).
Distribution: Distributed into the stratum corneum of the skin, nails, sebum, and hair. Enters breastmilk. Plasma protein binding: >99%.
Metabolism: Rapidly metabolised in the liver by CYP enzymes into inactive metabolites. Undergoes first-pass metabolism.
Excretion: Mainly via urine (80%, as inactive metabolites); faeces (20%). Terminal elimination half-life: 200-400 hr (prolonged use). Plasma elimination half-life: 17-36 hr (oral), 14-35 hr (topical).

Source: National Center for Biotechnology Information. PubChem Database. Terbinafine, CID=1549008, https://pubchem.ncbi.nlm.nih.gov/compound/Terbinafine (accessed on Jan. 23, 2020)

Store below 25°C. Protect from light and moisture.

Topical Antifungals & Antiparasites / Antifungals

D01AE15 - terbinafine ; Belongs to the class of other antifungals for topical use.
D01BA02 - terbinafine ; Belongs to the class of antifungals for systemic use.

Anon. Terbinafine (Systemic). Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 16/10/2017.

Anon. Terbinafine (Topical). Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 16/10/2017.

Buckingham R (ed). Terbinafine. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 16/10/2017.

Douglas Pharmaceuticals Ltd. Terbinafine-DP data sheet 10 December 2012. Medsafe. http://www.medsafe.govt.nz/. Accessed 16/10/2017.

Joint Formulary Committee. Terbinafine. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 16/10/2017.

Lamisil AT Gel (Novartis Consumer Health, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 19/10/2017.

Lamisil AT Spray (Novartis Consumer Health, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 19/10/2017.

Lamisil Tablet (Novartis Pharmaceuticals Corporation). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 19/10/2017.

McEvoy GK, Snow EK, Miller J et al (eds). Terbinafine Hydrochloride (Topical). AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 16/10/2017.

McEvoy GK, Snow EK, Miller J et al (eds). Terbinafine Hydrochloride. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 16/10/2017.