The auditory and vestibular toxicities induced by antiepileptic drugs

ABSTRACT

Introduction: Epilepsy is a chronic medical disease in one third of patients and is associated with comorbid adverse somatic conditions due to epilepsy itself or its long-term treatment with antiepileptic drugs (AEDs). Data from experimental, cross-sectional and prospective studies have evidence for the deleterious effect of some AEDs on the auditory and vestibular systems. These abnormalities may be reversible or irreversible.

Areas covered: This article review the evidence that long-term treatment with some antiepileptic drugs (AEDs) [e.g. carbamazepine, phenytoin, valproate, lamotrigine, gabapentin, vigabatrin and oxcarbazepine] (even in therapeutic drug doses) may result in tinnitus, phonophobia, sensorineural hearing loss, dizziness, ataxia, disequilibrium, imbalance, nystagmus, abnormalities in saccadic and pursuit eye movements and delayed conduction within the cochlea, auditory nerve and brainstem auditory pathways evidenced by abnormalities in Brainstem auditory evoked potentials and nystagmography recordings indicating auditory and central and/or peripheral vestibular dysfunctions.

Expert opinion: Identification of monitoring of patients at high risk for developing audio-vestibular manifestations is necessary for appropriate preventive and therapeutic measures.

KEYWORDS:

• Epilepsy
• antiepileptic drugs
• adverse effects
• carbamazepine
• valproate
• hearing loss
• imbalance
• nystagmus
• ototoxicity
• vestibular toxicity

Article highlights

• Epilepsy is a chronic medical disease and its treatment may be life-long.

• Chronic epilepsy and long-term treatment with antiepileptic drugs are associated with adverse somatic conditions

• The culprit AEDs are carbamazepine, phenytoin, valproate and lamotrigine, gabapentin, vigabatrin and oxcarbazepine.

• Tinnitus, phonophobia, sensorineural hearing loss, dizziness, ataxia, disequilibrium, imbalance are not uncommon with chronic AEDs therapy.

• Abnormalities in brainstem auditory and nystagmography are sensitive in detecting subclinical hearing or vestibular deficits.

• Audio-vestibular abnormalities may be reversible or irreversible.

• The proposed mechanisms for audiovestibular toxicity with AEDs include delayed conduction within the cochlea, auditory nerve and brainstem auditory pathways through GABA neurotransmitters or non-neurotransmitter mechanisms.

• Physicians should be aware of the possible cumulative auditory and/or vestibular adverse effects in patients with epilepsy.

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Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Additional information

Funding

This paper was not funded.