Can terbinafine (antifungal medication) lower the seizure threshold?

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Terbinafine and Seizure Threshold

Based on available evidence, terbinafine does NOT appear to lower seizure threshold and is not documented as a seizurogenic medication.

Evidence Assessment

The provided evidence does not establish any link between terbinafine and seizure risk:

  • No documented seizure risk: The British Association of Dermatologists' comprehensive safety profile for terbinafine does not list seizures or lowered seizure threshold among its known adverse effects 1

  • Known side effects are primarily non-neurological: The most common adverse effects include gastrointestinal disturbances (49% of reported side effects), dermatological events (23%), and rare hepatic toxicity—with no mention of neurological or seizure-related complications 1

Contrast with Medications That DO Lower Seizure Threshold

The evidence clearly documents which medications lower seizure threshold, and terbinafine is notably absent:

  • Antiviral medications: Amantadine shows an increased incidence of seizures in patients with seizure disorders, requiring close observation 2

  • Antibiotics: Amoxicillin is specifically noted to interact with "bupropion and other agents lowering seizure threshold" 2, and beta-lactams like meropenem have documented pro-convulsive activity 3

  • Psychotropic drugs: Antidepressants and antipsychotics are well-established seizure threshold reducers, with seizure incidence rates of 0.1-1.5% at therapeutic doses 4

Clinical Implications

  • Safe in seizure-prone patients: Unlike amantadine, rimantadine, or psychotropic medications, terbinafine does not require special monitoring or dose adjustments in patients with seizure disorders 1, 5, 6, 7

  • Low drug interaction potential: Terbinafine has a relatively low potential for drug interactions overall, which further supports its safety profile 6, 7, 8

  • Primary monitoring concerns: When prescribing terbinafine, focus on hepatic function (baseline liver function tests in high-risk patients) and renal function (contraindicated in renal impairment), not seizure risk 1

Important Caveat

  • The absence of documented seizure risk in extensive clinical use and post-marketing surveillance strongly suggests terbinafine does not lower seizure threshold 7, 8

  • If a patient on terbinafine experiences seizures, investigate other causes rather than attributing it to the antifungal medication 1

References

Guideline

Terbinafine Safety Profile

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Meropenem and Seizure Threshold

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Research

Terbinafine: a review of its use in onychomycosis in adults.

American journal of clinical dermatology, 2003

Research

Update on antifungal therapy with terbinafine.

Giornale italiano di dermatologia e venereologia : organo ufficiale, Societa italiana di dermatologia e sifilografia, 2010

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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