Terbinafine (Lamisil)

1. Health Canada Product Monograph — Terbinafine

• Lamisil tablets treat fungal nail infections (onychomycosis) caused by dermatophyte fungi.
• Lamisil tablets may also be used for severe skin infections such as ringworm (tinea corporis), jock itch (tinea cruris), and athlete's foot (tinea pedis) that have not responded to topical treatment.
• Lamisil cream treats fungal and yeast skin infections, including athlete's foot, ringworm, jock itch, and pityriasis (tinea) versicolor.
• Lamisil spray treats fungal skin infections and pityriasis versicolor, but is not effective for nail infections.

• Animal studies did not show evidence that terbinafine causes birth defects.
• Clinical experience with terbinafine in pregnant women is very limited.
• Lamisil tablets or cream should not be used during pregnancy unless the potential benefit clearly outweighs the potential risk.

• Terbinafine passes into breast milk, so mothers taking Lamisil tablets should not breastfeed.
• Nursing mothers should not apply Lamisil cream or spray to the breast area, and infants should not have contact with any treated skin.

• Blood levels and the drug's half-life are slightly higher in older adults.
• The overall rate of side effects related to terbinafine does not appear to differ from younger adults, but pre-existing liver or kidney impairment should be considered when prescribing.

• Safety and effectiveness of Lamisil have not been established in children.
• Lamisil should be kept out of the reach of children.

• The adult oral dose is 250 mg once daily.
• Treatment duration for nail infections is typically 6 weeks to 3 months, depending on which nail is affected and the severity of infection.
• Treatment duration for skin infections with tablets is typically 2 to 6 weeks, depending on the site and severity.
• Lamisil cream is applied once or twice daily for 1 to 2 weeks, depending on the infection being treated.
• Lamisil spray is applied once or twice daily for 1 week, depending on the infection being treated.
• Use in patients with kidney impairment is not recommended, since this has not been adequately studied.
• Lamisil tablets are contraindicated in patients with chronic or active liver disease.
• If a dose of tablets is missed, take it as soon as remembered, unless it is within about 4 hours of the next dose, in which case the missed dose should be skipped; do not double up.

If overdose is suspected, seek emergency medical attention immediately or contact your regional Poison Control Centre without delay.

• Reported overdose symptoms with tablets include headache, nausea, stomach pain, and dizziness.
• Treatment of tablet overdose involves activated charcoal to reduce further absorption and supportive care for symptoms.
• Accidental ingestion of a full tube of cream or bottle of spray delivers an amount of terbinafine roughly comparable to one tablet and could cause similar symptoms.
• The alcohol content of the spray should be considered if it is accidentally ingested in larger amounts.

• Headache may occur.
• Nausea may occur.
• Mild stomach pain or heartburn may occur.
• Diarrhea may occur.
• A feeling of fullness or bloating may occur.
• Loss of appetite may occur.
• Itchy skin rash may occur.
• Joint pain or muscle pain may occur.
• Altered or lost sense of taste may occur with tablets.
• Dizziness may occur with tablets.
• Tiredness may occur with tablets.
• With the cream or spray, flaking, peeling, redness, burning, or itching at the application site may occur.

Serious side effects require immediate discussion with the prescriber or emergency care.

• Serious, sometimes fatal, liver problems, including liver failure and the need for a liver transplant, have been reported with Lamisil tablets, in patients with and without pre-existing liver disease.
• Severe skin reactions, including Stevens-Johnson syndrome and toxic epidermal necrolysis, have been reported very rarely with tablets.
• Serious allergic reactions, including anaphylaxis and angioedema, can occur.
• Rare blood disorders, including low white blood cell counts and low platelet counts, have been reported with tablets.
• New or worsening lupus erythematosus, affecting the skin or the whole body, has been reported.
• Loss or disturbance of taste or smell, sometimes prolonged or permanent, has been reported with tablets.
• Vision or hearing disturbances, including tinnitus and reduced hearing, have been reported with tablets.
• Muscle breakdown (rhabdomyolysis) has been reported rarely with tablets.
• Inflammation of the pancreas (pancreatitis) has been reported rarely.
• Inflammation of blood vessels (vasculitis) has been reported.
• New or worsening depression or anxiety has been reported, sometimes linked to taste disturbances.
• Seek urgent medical attention for yellowing of the skin or eyes, dark urine, pale stools, persistent nausea, or unusual tiredness, which may signal a liver problem.

• Use tablets with caution and obtain baseline liver function tests before starting, given the risk of serious liver toxicity.
• Monitor liver function periodically, generally after 4-6 weeks of tablet treatment.
• Use tablets with caution in patients with pre-existing psoriasis or lupus, since these conditions may worsen.
• Use tablets with caution in patients taking drugs with a narrow therapeutic window that are broken down by the CYP2D6 enzyme, such as certain antidepressants, beta-blockers, and antiarrhythmics.
• Use cream and spray with caution near the eyes, since they can be irritating on contact.
• Avoid applying the spray to the face.
• Use the spray with caution on broken or irritated skin, since its alcohol content can sting or irritate.
• Discontinue tablets promptly if visual, hearing, taste, or smell disturbances develop.

• Contraindicated in patients with known hypersensitivity to terbinafine or any ingredient in the formulation.
• Lamisil tablets are contraindicated in patients with chronic or active liver disease.

• Rifampicin increases the clearance of terbinafine and can reduce its effectiveness.
• Cimetidine decreases the clearance of terbinafine, which can raise terbinafine levels.
• Fluconazole increases terbinafine levels by inhibiting the enzymes that break it down.
• Terbinafine inhibits the CYP2D6 enzyme and can raise the levels of drugs metabolized by it, including certain tricyclic antidepressants, beta-blockers, SSRIs, and antiarrhythmic medicines.
• Terbinafine significantly reduces the breakdown of desipramine, roughly doubling its levels.
• Terbinafine can affect the metabolism of dextromethorphan, a cough suppressant, converting some people into poor metabolizers of the drug.
• Some menstrual irregularities have been reported when tablets are taken with oral contraceptives, though not more often than with contraceptives alone.
• Terbinafine does not significantly affect the levels of digoxin, antipyrine, or fluconazole itself.
• Lamisil cream and spray have no known drug interactions, since very little is absorbed into the bloodstream.

• Lamisil tablets can be taken on an empty stomach or with food; either is fine, and food has only a small effect on absorption that does not require a dose change.

• Tablets should be taken at the same time each day, with or without food, to help with remembering doses; time of day otherwise does not matter.
• Cream and spray are applied to clean, dry skin once or twice daily as directed, independent of meals.

• Store tablets at 15°C to 30°C and protect them from light.
• Store cream and spray at room temperature.
• Keep out of the reach and sight of children.

• Lamisil (terbinafine) tablets treat fungal nail infections and stubborn skin infections, while the cream and spray treat milder skin infections like athlete's foot and ringworm.
• Complete the full course of treatment even if your symptoms improve early, since fungal infections can flare back up if treatment stops too soon.
• Tell your healthcare professional right away if you develop nausea, loss of appetite, dark urine, or yellowing of your skin or eyes while taking the tablets, since these can be signs of a liver problem.
• Avoid getting the cream or spray in your eyes, and do not use the spray on your face.
• You will need blood tests before and during tablet treatment to monitor your liver.