Peer-review started: September 10, 2022
First decision: October 24, 2022
Revised: October 25, 2022
Accepted: October 31, 2022
Article in press: October 31, 2022
Published online: November 15, 2022
Processing time: 64 Days and 12.7 Hours
Clarithromycin is a macrolide antibiotic commonly prescribed to patients with upper respiratory and otolaryngological infections. Neuropsychiatric adverse effects of clarithromycin include agitation, insomnia, delirium, psychosis, and seizure.
A 52-year-old man was admitted to our hospital with a convulsion. He had > 10-year history of clarithromycin intake for chronic sinusitis. One week before admission, he started to take diltiazem for angina pectoris. On admission, his convulsion subsided. His electroencephalography showed frontal intermittent rhythmic delta activity. One week after he ceased clarithromycin, his electroencephalographic abnormalities disappeared. We suggested that the patient developed convulsions due to increased blood levels of clarithromycin caused by oral administration of diltiazem, which is involved in CYP3A metabolism.
Clarithromycin has a relatively high safety profile and is a frequently prescribed drug. However, there are a few previous reports of clarithromycin-related convulsive disorders. Clinicians should be aware of the drug interaction and rare side effects of seizures.
Core Tip: Clarithromycin is a frequently used medication and has a long history of use. The rarity of reports of convulsions induced by clarithromycin suggests that the induction of convulsions by clarithromycin is a rare phenomenon or has been overlooked. Clarithromycin is a frequently prescribed drug but has many interactions. Therefore, we report this case as a cautionary statement for all neurologists. Also, the measurement of QT time may be a valuable method of assessing clarithromycin excess.