Visual hallucinations associated with zonisamide.
Zonisamide is a broad-spectrum antiepileptic drug used to treat various types of seizures. Although visual hallucinations have not been reported as an adverse effect of this agent, we describe three patients who experienced complex visual hallucinations and altered mental status after zonisamide treatment was begun or its dosage increased. All three had been diagnosed earlier with epilepsy, and their electroencephalogram (EEG) findings were abnormal. During monitoring, visual hallucinations did not correlate with EEG readings, nor did video recording capture any of the described events. None of the patients had experienced visual hallucinations before this event. The only recent change in their treatment was the introduction or increased dosage of zonisamide. With either discontinuation or decreased dosage of the drug the symptoms disappeared and did not recur. Further observations and reports will help clarify this adverse effect. Until then, clinicians need to be aware of this possible complication associated with zonisamide.
Akman
Cigdem I
CI
Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.
Goodkin
Howard P
HP
Rogers
Donald P
DP
Riviello
James J
JJ
D000293:Adolescent; D000328:Adult; D000927:Anticonvulsants / Q000009:adverse effects* / Q000627:therapeutic use; D002648:Child; D005260:Female; D006212:Hallucinations / Q000139:chemically induced*; D006801:Humans; D018887:Landau-Kleffner Syndrome / Q000188:drug therapy*; D012640:Seizures / Q000188:drug therapy*; D014635:Valproic Acid / Q000009:adverse effects* / Q000627:therapeutic use
D000927:Anticonvulsants; D014635:Valproic Acid