Clarithromycin raises
carbamazepine levels by 20 to 50%, despite dosage reductions of up to 40%. Several cases of
toxicity have been seen.
Monitor
carbamazepine levels and adjust the dose accordingly. It has been recommended that
carbamazepine doses are reduced by 30 to 50% and patients monitored within 3 to 5 days of starting
clarithromycin.
Carbamazepine toxicity may present as nausea, vomiting, ataxia or drowsiness. Azithromycin appears not to interact and may therefore be a suitable alternative.