Drug adherence in Parkinson's disease.

Physicians modify drug schedules in response to their patients' clinical responses. Failure to relieve patients' symptoms or the emergence of drug-related side effects may reflect nonadherence to a prescribed drug schedule rather than incorrect therapeutic physician decisions. Using a medication questionnaire and a computerized medication event monitoring system (MEMS) to monitor medication use, nonadherence of drug use was examined in subjects with Parkinson's disease (PD).