Examination of the safety and use of apomorphine prescribed in general practice in England as a treatment for erectile dysfunction

Abstract

To examine the safety and use of apomorphine as prescribed in general medical practice in England as a treatment for erectile dysfunction (ED). Apomorphine hydrochloride (marketed as Uprima, Abbott Laboratories Ltd, UK) is licensed in the UK as a sublingual therapy for ED. It is the first treatment for ED with a central mode of action. This postmarketing observational cohort study was conducted using prescription-event monitoring (PEM) methods. Exposure information was obtained from dispensed prescription data for patients first prescribed apomorphine between October 2001 and December 2002. Outcome data were derived from Green-Form questionnaires posted to prescribing physicians > or = 6 months after the date of the first apomorphine prescription for each patient. The study cohort comprised 11 185 patients, 99.3% (11,111) of whom were men, with a median (interquartile range) age of 61 (54-68) years. The most frequently reported prescribing indication was ED and the most frequently reported reason for stopping apomorphine was that it was 'not effective'. In addition, the percentage of patients for whom apomorphine was reported to have been effective was relatively low. Headache was the most commonly reported adverse drug reaction, and the most frequently reported clinical condition occurring in the first month of observation. A small number of events (24) were reported that were not listed in the current Summary of Product Characteristics (SPC) and were considered by the prescribing general practitioner (GP) to be associated with apomorphine use. The proportion of patients for whom apomorphine was reported to be effective was low. Also, 'not effective' was the most frequently reported event and a high percentage of patients stopped apomorphine because it was 'not effective'. The most frequently reported clinical adverse events (headache and nausea) were those listed in the SPC. A small number of reports for unlabelled events were thought by prescribers to be related to apomorphine use. The confounding factors of patient age and coexisting disease should be considered when assessing data from this study.