Concurrent administration of donepezil HCl and levodopa/carbidopa in patients with Parkinson's disease: assessment of pharmacokinetic changes and safety following multiple oral doses

Abstract

No clinically significant drug-drug interactions between donepezil HCl and levodopa/carbidopa were observed at steady state. The small changes in the pharmacokinetics of levodopa did not result in any change in motor symptoms. Co-administration of the two drugs led to a small increase in adverse events compared with administration of levodopa/carbidopa alone in PD patients. These adverse events, however, were consistent with donepezil's cholinomimetic effect, and their incidence was comparable to that observed following the administration of donepezil HCl alone.