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Terbinafine

Antibioticprescriptionoral · inferred

Allylamine antifungal inhibiting squalene epoxidase, first-line for dermatophyte onychomycosis. Highly lipophilic, concentrating in skin, hair, and nails where it persists for weeks after plasma clearance. Plasma half-life ~22 h but terminal tissue half-life 200-400 h. Typical 250 mg once daily for 6 (fingernail) or 12 weeks (toenail).

Projected serum levels — 250 mg, once daily

Terbinafine
Terbinafine modeled serum levels, 250 mg once daily over 15 days Population-based pharmacokinetic estimate. Steady state reached after approximately 2 days. 0 50 100 150 200 Day 0 Day 4 Day 8 Day 11 Day 15 Time on a regular schedule ≈ steady state · day 2
Terbinafine modeled serum levels with a loading dose of 396 mg, then 250 mg once daily The first dose is larger so levels approach steady state faster. 0 50 100 150 200 Day 0 Day 4 Day 8 Day 11 Day 15 Time on a regular schedule

Maintenance schedule: 250 mg once daily (oral).

Loading schedule: 396 mg on day 1, then 250 mg once daily — reaching therapeutic levels sooner.

Modeled steady state after ~2 days: peak ≈ 145 mg, trough ≈ 60.2 mg body load. Population-based estimate over 15 days for a 250 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
Antibiotic
Route modeled
Oral
Model confidence
inferred
Half-life
17 h
Common dose
250 mg
Suggested maximum
250 mg/day
Reference dose range
125–250 mg (single dose)
Suggested cadence
once daily
Validated against
250 mg oral — Cmax 1 mg/L at 2 h

Documented interactions

  • danger
    4-MMC (Mephedrone) + Terbinafine CYP inhibition

    Terbinafine reversible_inhibitor of CYP2D6 predicted to change 4-MMC (Mephedrone) AUC by ~2.27x

  • danger
    6-APB (Benzofury / 6-(2-aminopropyl)benzofuran) + Terbinafine CYP inhibition

    Terbinafine reversible_inhibitor of CYP2D6 predicted to change 6-APB (Benzofury / 6-(2-aminopropyl)benzofuran) AUC by ~3.33x

  • danger
    Amphetamine (Adderall) + Terbinafine CYP inhibition

    Terbinafine reversible_inhibitor of CYP2D6 predicted to change Amphetamine (Adderall) AUC by ~2.11x

  • danger
    Atomoxetine (Strattera) + Terbinafine CYP inhibition

    Terbinafine reversible_inhibitor of CYP2D6 predicted to change Atomoxetine (Strattera) AUC by ~2.68x

  • danger
    Carbamazepine (Tegretol) + Terbinafine CYP induction

    Carbamazepine (Tegretol) inducer of CYP3A4 predicted to change Terbinafine AUC by ~0.47x

  • danger
    Dextromethorphan (DXM) + Terbinafine CYP inhibition

    Terbinafine reversible_inhibitor of CYP2D6 predicted to change Dextromethorphan (DXM) AUC by ~2.47x

Serum checks 294 modeled interaction pairings for terbinafine across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. Onychomycosis in the 21st century: an update on diagnosis, epidemiology, and treatment Gupta AK, Stec N, Summerbell RC et al. · Journal of the European Academy of Dermatology and Venereology, 2020 DOI

    Contemporary review reaffirming oral terbinafine 250 mg/day as first-line therapy for dermatophyte onychomycosis, with higher complete cure rates than azoles.

  2. Terbinafine: a review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in superficial mycoses Balfour JA, Faulds D · Drugs, 1992 DOI

    Foundational PK/PD review establishing terbinafine's ~40% bioavailability, plasma half-life ~22 hours, prolonged tissue retention in stratum corneum and nails, and fungicidal activity against dermatophytes.

  3. Continuous Oral Terbinafine Compared with Intermittent Oral Itraconazole in the Treatment of Toenail Onychomycosis Evans EGV, Sigurgeirsson B · BMJ, 1999 DOI

    LION study randomizing 496 patients to terbinafine vs itraconazole demonstrated significantly higher mycological and clinical cure rates with terbinafine for toenail onychomycosis.

3 published studies referenced in the app, each with a plain-language summary.