can cause a transient moderate (30%) rise in serum phenobarbital
levels. Primidone is metabolised to phenobarbital
and may therefore interact similarly.
Warn the patient to monitor for indicators of phenobarbital toxicity
(drowsiness, ataxia or dysarthria), and take levels if necessary. Levels may still be moderately raised after 28 days. However, most patients seem unlikely to require dosage adjustments.