terbinafine (systemic)

Contraindicated in:

Hypersensitivity;
Chronic or active liver disease;
HF or left ventricular dysfunction.

Use Cautiously in:

History of alcoholism;
Renal impairment (dose ↓ recommended for CCr <50 mL/min);
OB: Safety not established in pregnancy;
Lactation: Use while breastfeeding only if maternal benefit justifies potential risk to infant;
Pedi: Safety and effectiveness not established in children.

Adv. Reactions/Side Effects ⬆ ⬇

CV: HF

Derm: DRUG REACTION WITH EOSINOPHILIA AND SYSTEMIC SYMPTOMS (DRESS), itching, rash, STEVENS-JOHNSON SYNDROME (SJS), TOXIC EPIDERMAL NECROLYSIS (TEN)

EENT: nasopharyngitis, smell disturbance

GI: anorexia, diarrhea, nausea, stomach pain, vomiting, drug-induced hepatitis, HEPATOTOXICITY, taste disturbance

Hemat: hemolytic uremic syndrome, neutropenia, pancytopenia, thrombotic thrombocytopenic purpura

Neuro: depression, headache

Resp: cough

Misc: fever

Interactions ⬆ ⬇

Drug-drug:

Alcohol or other hepatotoxic agents may ↑ risk of hepatotoxicity.
Rifampin may ↓ effectiveness.
Fluconazole and cimetidine may ↑ levels.
May ↑ effects of CYP2D6 substrates, including tricyclic antidepressants, selective serotonin reuptake inhibitors, beta blockers, flecainide, and propafenone.

Drug-Natural Products:

↑caffeine levels and side effects with caffeine-containing herbs (cola nut, guarana, mate, tea, coffee).

Availability ⬆ ⬇

(Generic available)

Tablets: 250 mg

Route/Dosage ⬆ ⬇

PO (Adults ): 250 mg once daily for 6 wk for fingernail infection or 12 wk for toenail infection.

Action ⬆ ⬇

Interferes with fungal cell wall synthesis (ergosterol biosynthesis) by inhibiting the enzyme squalene epoxidase.

Therapeutic effects:

Fungal cell death.

Spectrum:

Active against dermatophytes and other fungi.

Classifications ⬆ ⬇

Therapeutic Classification: antifungals

Pharmacokinetics ⬆ ⬇

Absorption: 70–80% absorbed after oral administration.

Distribution: Extensively distributed; penetrates dermis and epidermis; concentrates in stratum corneum, hair, scalp, and nails.

Protein Binding: 99%.

Metabolism/Excretion: Extensively metabolized by the liver by the CYP1A2, CYP2C9, CYP2C19, and CYP3A4 isoenzymes.

Half-Life: Plasma: 22 days; longer from skin and nails.

Canadian Brand Names ⬆ ⬇

Time/Action Profile ⬆ ⬇

(antifungal tissue concentrations)

ROUTE	ONSET	PEAK	DURATION
PO	several days	days–wk	several wk

Patient/Family Teaching ⬆ ⬇

Instruct patient to take medication as directed, for the full course of therapy, even if feeling better. Doses should be taken at the same time each day. Advise patient to read Medication Guide before starting therapy and with each Rx refill in case of changes.
Instruct patient to notify health care professional immediately if signs and symptoms of liver dysfunction (unusual fatigue, anorexia, nausea, vomiting, upper right abdominal pain, jaundice, dark urine, or pale stools), depression, or rash occur. Terbinafine should be discontinued.
May cause disturbance in taste and smell. Advise patient to notify health care professional if this or poor appetite, weight loss, or anxiety occur.
Advise patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
Rep: Advise patient to notify health care professional if pregnancy is planned or suspected or if breastfeeding.

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Indications ⬇

Contraind./Precautions ⬆ ⬇