[Adverse drug events in out-patients as the cause of an initial consultation to neurology].
INTRODUCTION: The aim of this study was to determine the incidence and type of neurological adverse drug events as the cause of an initial consultation to neurology, identify the medications involved and evaluate the possibilities of prevention. METHODS: Prospective observational study lasting 1 year (February 10, 2004 to February 9, 2005) that included all new adult outpatients at a neurology ward. Suspected adverse drug events were evaluated by two investigators in order to establish causality relationships, severity, preventability and types of medication errors associated with the preventable cases. RESULTS: In a total of 685 patients who attended the neurology consult, 60 neurological adverse drug events were detected (8.7%), of which 70% were moderate and 30% mild. The most frequent adverse events detected were medication overuse headache (51.6%), mainly due to acetaminophen and ergot derivatives, and drug-induced Parkinsonism (33.3%), especially related to trimetazidine or sulpiride. Fifty-five adverse events (91.6%) were considered potentially preventable. Medication errors associated were overuse and self-medication (33.7 %), failure to follow treatment adequately (25.6%), excessive duration of treatment (16.3%) and prescribing an unnecessary medication (14.0%) or an inappropriate one (10.5%). CONCLUSIONS: The incidence of adverse drug events motivating an initial visit to a neurologist is high and the majority of these cases are preventable. Greater knowledge on the part of physicians concerning medication overuse headache and drugs that induce Parkinsonism, as well as public health education on the risks involved with the use of analgesics, could contribute to prevention.