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

Aim: The use of acetylcholinesterase inhibitors for the treatment of comorbid Alzheimer's disease in Parkinson's disease (PD) patients stabilized on a levodopa regimen may potentially disrupt cholinergic balance. This randomized, double-blind, crossover study investigated the safety of, and possible drug-drug interaction between, donepezil HCl and levodopa/carbidopa.

Methods: Twenty-five patients with PD who were taking physician-optimized doses of levodopa/carbidopa (with daytime dosing intervals of 4-8 h) were administered once-daily doses of either donepezil HCl (5 mg) or placebo for 15 days, in two treatment periods, separated by a washout of at least 2 weeks.

Role of integrative pharmacokinetic and pharmacodynamic optimization strategy in the management of Parkinson"s disease patients experiencing motor fluctuations with levodopa.

Parkinson's disease is a progressively debilitating motor neuron disease that affects the dopaminergic neurons within the nigral-striatal and surrounding pathways and which is characterized clinically by rigidity, resting tremor and bradykinesia with or without postural imbalance. Levodopa is the "gold standard" for the treatment and management of Parkinson's disease worldwide. However, following prolonged use of the drug, the "honey-moon" which was once enjoyed by patients on levodopa begins to wane.