LAMIFEN 250/MG TAB 14/TAB

Indications

Approved Uses

Onychomycosis of the toenail or fingernail due to dermatophytes (tinea unguium).

Off-Label Uses

Off-label: Some non-dermatophyte superficial fungal infections have been treated with oral terbinafine, but it is generally not effective for pityriasis (tinea) versicolor and is not a preferred agent for cutaneous candidiasis; oral use for routine tinea pedis/cruris/corporis is typically on-label or guideline-supported when systemic therapy is needed (not off-label).

Dosage & Administration

Dosing by Condition

Adults: Onychomycosis-250 mg once daily for 6 weeks (fingernail) or 12 weeks (toenail). Tinea capitis-250 mg once daily typically 4-6 weeks. Tinea corporis/cruris-250 mg once daily for 2-4 weeks. Tinea pedis-250 mg once daily for 2-6 weeks (when oral therapy is indicated).

Initial Dose

250mg once daily.

Maintenance Dose

250mg once daily.

Maximum Dose

250mg per day

Children's Dosage

Tinea capitis (children ≥4 years or >20kg): weight-based dosing - <20kg: 62.5mg/day; 20-40kg: 125mg/day; >40kg: 250mg/day for 4 weeks. Not approved for onychomycosis in children.

Dose Adjustment Notes

Avoid/contraindicated in chronic or active liver disease; not recommended in severe renal impairment (e.g., CrCl <50 mL/min) due to reduced clearance/limited data; no routine dose titration for standard adult indications.

How to Take

Swallow the tablet whole with water; may be taken with or without food; take once daily at the same time each day and complete the full prescribed course.

Side Effects

Common Side Effects

Headache; gastrointestinal upset (diarrhea, dyspepsia, nausea, abdominal pain); rash/urticaria; taste disturbance (dysgeusia); and possible elevations in liver enzymes.

Side Effect Frequency

Very common (≥10%): headache; gastrointestinal effects (e.g., diarrhea, dyspepsia, nausea, abdominal pain/fullness). Common (1-10%): rash/pruritus/urticaria, taste disturbance, liver enzyme elevations. Rare/very rare: hepatotoxicity/liver failure, serious skin reactions (SJS/TEN), blood dyscrasias (e.g., neutropenia/agranulocytosis).

Safety & Warnings

Contraindications

Hypersensitivity to terbinafine (or any excipient) and chronic or active liver disease.

Warnings & Precautions

Baseline liver function tests before starting and repeat if symptoms/signs of liver injury occur (routine periodic monitoring is commonly recommended in practice); stop terbinafine if hepatotoxicity or severe rash occurs; counsel on taste/smell disturbance (may be prolonged) and discontinue if severe; consider CBC if immunocompromised or if symptoms of infection occur/therapy is prolonged; use caution in psoriasis and lupus due to possible exacerbation.

Age Restriction

For this product (oral terbinafine 250 mg tablet): onychomycosis-safety/efficacy not established in pediatric patients (<18 years); tinea capitis-pediatric use is supported for age ≥4 years in some jurisdictions but is not an approved indication for the 250 mg tablet in many labels (often oral granules are the labeled pediatric formulation).

Drug Interactions

Drug Interactions

Key interactions: rifampin decreases terbinafine exposure (induces metabolism); cimetidine increases terbinafine exposure (inhibits metabolism); terbinafine inhibits CYP2D6-can increase effects/levels of CYP2D6 substrates (e.g., TCAs, SSRIs, some beta-blockers, antiarrhythmics, dextromethorphan; may reduce codeine/tramadol activation); warfarin-possible INR changes; cyclosporine-may reduce cyclosporine concentrations; strong azole inhibitors (e.g., fluconazole) can increase terbinafine exposure.

Interaction Severity

MAJOR/clinically significant: Rifampin (markedly decreases terbinafine exposure); strong CYP2D6-substrate drugs with narrow therapeutic index may require close monitoring/dose adjustment due to terbinafine CYP2D6 inhibition (e.g., some TCAs/SSRIs, certain beta-blockers, antiarrhythmics). MODERATE: Cimetidine/other CYP inhibitors (increase terbinafine levels); warfarin (reports of INR changes-monitor); cyclosporine (possible level reduction-monitor). SPECIAL NOTE: Tamoxifen effectiveness may be reduced via CYP2D6 inhibition (clinically important).

Food Interaction

No clinically significant food interaction; may be taken with or without food.

Special Populations

Pregnancy

Category B

Children

Tinea capitis (children ≥4 years or >20kg): weight-based dosing - <20kg: 62.5mg/day; 20-40kg: 125mg/day; >40kg: 250mg/day for 4 weeks. Not approved for onychomycosis in children.

Elderly

Standard adult dosing; monitor renal and hepatic function as age-related decline may affect drug clearance

Liver Impairment

Contraindicated in chronic or active liver disease; avoid/not recommended in patients with hepatic impairment and discontinue if liver injury develops.

Storage & Patient Advice

Missed Dose

Take the missed dose as soon as remembered unless it is close to the next scheduled dose; if close, skip the missed dose and resume the regular schedule-do not double doses.

Stopping the Medicine

Do not stop early without prescriber advice; complete the prescribed course, and stopping is appropriate once the full course is completed or if significant adverse effects occur and a clinician instructs discontinuation.

Patient Counseling

Complete the prescribed course; take once daily and may be taken with or without food. Seek urgent medical advice and stop the medicine if signs of liver injury occur (persistent nausea/vomiting, loss of appetite, unusual fatigue, dark urine, pale stools, jaundice) or if a new/worsening rash or blistering occurs. Report taste or smell changes (may persist after stopping). Avoid or minimize alcohol and inform the prescriber/pharmacist about all other medicines (notably warfarin/other anticoagulants, antidepressants/TCAs/SSRIs, beta‑blockers, antiarrhythmics, cimetidine, rifampicin, cyclosporine) due to interaction potential. For nail infections, visible improvement may take months after finishing therapy; do not share medication.

Monitoring Requirements

Obtain baseline liver function tests before starting; repeat LFTs if symptoms/signs of hepatotoxicity occur (and consider repeat during prolonged courses per local practice). Consider CBC if clinical features suggest blood dyscrasia.

Pharmacology

Mechanism of Action

Inhibits squalene epoxidase, a key enzyme in fungal ergosterol biosynthesis, leading to squalene accumulation and ergosterol deficiency, causing fungal cell membrane disruption and cell death (fungicidal)

Onset of Action

Antifungal activity begins soon after initiation, but clinical improvement-especially for onychomycosis-may not be evident until weeks to months and can continue after therapy as the nail grows out.

Duration of Effect

Terbinafine persists in keratinized tissues (skin, hair, nails) for weeks to months after stopping therapy, especially in nails.

Half-Life

Effective plasma half‑life ~36 hours; terminal half‑life ~200-400 hours due to slow release from skin/adipose/nail tissues.

Bioavailability

Approximately 70% oral bioavailability (systemic availability reduced by first‑pass metabolism).

Metabolism

Extensive hepatic metabolism via multiple CYP enzymes (notably CYP2C9, CYP1A2, CYP3A4, CYP2C8, CYP2C19) and terbinafine is a CYP2D6 inhibitor.

Excretion

Primarily renal excretion as metabolites (~70% in urine) with the remainder mainly in feces (~20-30%).

Protein Binding

>99%

Product Information

Available Dosage Forms

For this SFDA product (LAMIFEN): Oral tablet only.

Composition per Dose

Each tablet: 250mg terbinafine as terbinafine hydrochloride.

Generic Availability

Yes

OTC Alternatives

For superficial skin tinea (not nails/scalp): OTC topical antifungals such as terbinafine 1% cream/gel/spray (where OTC), clotrimazole 1%, or miconazole 2%; oral terbinafine (this product) is prescription-only per SFDA.

Application

Oral

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