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). We report that prescription nonadherence in PD subjects was common and approximated that reported in other chronic diseases. During a 28-day observation period, only 4 of 39 subjects had complete schedule adherence, i.e., no missed, extra, or mistimed doses. Using a questionnaire, 24.3% of subjects acknowledged missing any doses but the computerized MEMS recorded that 51.3% of subjects missed at least one dose per week and 20.5% of subjects missed three or more doses per week. Mistiming of doses was admitted by 73% of subjects but 82.1% had recorded mistimed doses. Of multiple sociodemographic and disease-related items examined, only gender and level of education were statistically related to nonadherence.