Terbinafine

Selected 250 mg tablets treat dermatophyte onychomycosis of fingernails/toenails. Confirm infection with an appropriate nail specimen for KOH, fungal culture or biopsy before treatment. In vitro activity against other organisms is not an expanded labeled indication.

Current 1% cream/spray treat labeled athlete’s foot between toes, jock itch and ringworm; cream also has bottom/side-of-foot directions, whereas selected spray states effectiveness there is unknown. Both prohibit nail/scalp use. Discontinued Lamisil oral granules were approved for tinea capitis at age ≥ 4; that historical formulation-specific approval is not a current tablet pediatric indication.

250 mg once daily: fingernails 6 weeks; toenails 12 weeks. Take with or without food. Benefit becomes apparent months later as a healthy nail grows. If missed, take when remembered unless the next dose is less than 4 hours away; then skip, never double. No universal pulse regimen or automatic repeat course is supplied.

Wash and dry affected skin first. Cream: between toes twice daily for 1 week; bottom/sides of foot twice daily for 2 weeks; jock itch/ringworm once daily for 1 week. Spray: between toes twice daily for 1 week; jock itch/ringworm once daily for 1 week; effectiveness on bottom/sides of foot is unknown. Below 12 ask a doctor. Use externally and complete the exact product course; do not extrapolate either schedule to nails/scalp.

FDA March2019 PI: tinea capitis at age ≥ 4, once daily with food for 6 weeks. Weight < 25 kg: 125 mg/day; 25–35 kg: 187.5 mg/day; > 35 kg: 250 mg/day. Sprinkle packets on pudding or other nonacidic soft food such as mashed potatoes and swallow without chewing; not applesauce/fruit-based food. NDA022071 is currently Discontinued. Verify an available exact formulation and current specialist directions rather than substitute/crush tablets or assert current granule supply.

Oral treatment is contraindicated in chronic/active liver disease. At creatinine clearance ≤ 50 mL/min, use has not been adequately studied; renal impairment or cirrhosis reduces clearance about 50%. This is not a label-directed 50% dose reduction. Assess suitability rather than invent a renal algorithm; topical Drug Facts supply no corresponding numeric organ regimen.

Oral tablets: chronic/active liver disease or history of allergy to oral terbinafine, including anaphylaxis risk. Topical labels have route/site restrictions; do not automatically transfer oral hepatic contraindications to external products. Ingredient allergy still requires avoiding the affected formulation.

The selected current oral and topical labels have no boxed warning. Oral hepatotoxicity, blood disorders, serious skin reactions and other systemic precautions remain significant.

Oral trials commonly report headache, GI symptoms, rash/pruritus/urticaria, taste changes and liver-enzyme abnormalities. Serious postmarketing reports include liver failure, cytopenias/TMA, anaphylaxis, lupus, severe skin reactions, sensory/hearing/visual changes and rhabdomyolysis; reports do not establish incidence. Topicals can irritate the application site. Oral overdose can cause nausea/vomiting, abdominal pain, dizziness, rash and headache; seek medical/Poison Help advice. Accidental topical ingestion needs prompt assessment, not an oral-dose conversion.

Terbinafine inhibits CYP2D6: TCAs, SSRIs, beta blockers, class1C antiarrhythmics and MAO-B inhibitors may need monitoring and co-drug reduction. Desipramine exposure rose in a study, with effects still present 4 weeks after stopping terbinafine. Rifampin increases clearance; cimetidine reduces it; fluconazole and inhibitors of both CYP2C9/3A4 can increase exposure. Warfarin PT changes in either direction are reported with uncertain causality; review INR monitoring. Cyclosporine clearance increased and caffeine clearance decreased in studies. Adequate oral-contraceptive interaction studies are lacking; in vitro findings are not a contraceptive-effectiveness guarantee. These oral data do not establish the same systemic interaction burden for OTC topicals.

Safety/effectiveness of oral tablets for pediatric onychomycosis are unestablished. Current OTC topical directions begin at 12; younger children need medical advice. Historical granules separately establish tinea-capitis approval at ≥ 4. Oral geriatric evidence is limited; consider hepatic, renal, cardiac disease and interacting medicines rather than a fixed age-only adjustment.

Oral human pregnancy data are insufficient to establish risk. Terbinafine is in human milk; infant-effect/milk-production data are limited. Discuss maternal need, breastfeeding benefits and potential infant effects. Do not present oral exposure data as a numeric topical regimen or absolute route-independent safety claim.

Active/chronic liver disease contraindicates oral tablets, and pretreatment/periodic LFTs are recommended even without known disease. Oral use at creatinine clearance ≤ 50 mL/min is inadequately studied; reduced clearance does not supply an approved reduction formula. Refer organ dysfunction for individualized therapy selection.

An allylamine that inhibits fungal squalene epoxidase, causing ergosterol deficiency and squalene accumulation. Oral absorption exceeds 70%, with about 40% bioavailability after first-pass metabolism; peak approximately 2 hours and protein binding > 99%. Multiple CYP enzymes metabolize terbinafine; about 70% of administered dose is eliminated in urine as metabolites. Effective half-life about 36 hours and terminal tissue-release half-life 200–400 hours describe different phases, not permission for intermittent dosing.

Confirm fungal nail infection before oral treatment. Assess liver disease, baseline and periodic LFTs, interacting drugs, rash, taste/smell, mood, nutrition and treatment response. Use CBC for infection symptoms and consider it during prolonged treatment in immunodeficiency; unexplained anemia/platelet decline requires TMA assessment. Renal disease affects therapy selection. There is no routine therapeutic terbinafine blood-level target.

Finish the exact route/indication course; do not substitute a skin cream for nail/scalp therapy. Stop oral tablets and contact the clinician promptly for jaundice, dark urine, pale stools, persistent GI symptoms, severe rash, taste/smell change or mood symptoms. Emergency care is needed for breathing/swelling or serious systemic symptoms. Wash hands after cream; apply spray thinly from 4–6 inches, clean the opening and recap. Keep topicals out of eyes/mouth and never swallow.

Selected repackaged 250 mg white/off-white round uncoated tablet, D / 74; NDC70518-2941-00, 30-tablet blister. Verify the original package and repackaging label; the identifier does not establish local stock.

Current selected prescription tablets 250 mg; OTC topical cream and spray 1% terbinafine hydrochloride. FDA selected ANDA078297 is Prescription; ANDA077511 and NDA021124 selected topicals are OTC. Lamisil oral granules 125 mg and 187.5 mg per packet, NDA022071, are currently Discontinued. No oral/topical or tablet/granule interchangeability is inferred.

Oral selected tablets: 20–25°C, excursions 15–30°C, protect from light. Selected cream/spray: 20–25°C; follow seals/caps and expiry. Spray container is pressurized: do not puncture/incinerate or expose above 49°C (120°F). Keep all products away from children; topical containers are not oral dispensers.