Carbamazepine-Induced Paroxysmal Dysarthria and Ataxia in an Elderly Patient: A Case Report and Clinical Considerations.

To report a case of carbamazepine-induced neurotoxicity presenting as paroxysmal dysarthria with ataxia, and to highlight clinical risk factors and diagnostic challenges. This case mimicked a transient ischemic attack (TIA), representing a significant diagnostic pitfall. We present the case of a 71-year-old woman who developed acute paroxysmal dysarthria and ataxia after initiating carbamazepine for otoneuralgia. Differential diagnoses considered included TIA, seizure, drug-induced neurotoxicity, and vestibular disorders. Diagnosis was established through medication review, temporal correlation, and a positive rechallenge test. The Naranjo Adverse Drug Reaction Probability Scale was applied. Symptoms resolved completely upon drug withdrawal and recurred immediately after re-exposure (the patient self-administered a single 100 mg dose on day 4, with immediate symptom recurrence, confirming causality). Serum drug levels were not measured due to limitations of our hospital's laboratory facilities; the Naranjo score was 5 (probable ADR). This case illustrates that carbamazepine may induce specific neurotoxicity even at standard doses in susceptible elderly patients. Paroxysmal dysarthria is a rare but underrecognized adverse reaction. Key clinical take-home points include vigilant clinical assessment, caution with potential drug-drug interactions, therapeutic drug monitoring, and pharmacogenetic profiling when indicated- all of which may aid in prevention and risk reduction.