POSTMARKETING SURVEILLANCE STUDY OF A NON-CHLOROFLUOROCARBON INHALER ACCORDING TO THE SAFETY ASSESSMENT OF MARKETED MEDICINES GUIDELINES

Objective To evaluate the safety of a non-chlorofluorocarbon metered d ose salbutamol inhaler. Design This was a postmarketing surveillance s tudy, conducted under formal guidelines for company sponsored safety a ssessment of marketed medicines (SAMM). A non-randomised, non-interven tional, observational design compared patients prescribed metered dose s of salbutamol delivered by inhalers using either hydrofluoroalkane o r chlorofluorocarbon as the propellant. Follow up was three months. Se tting 646 general practices throughout the United Kingdom. Subjects 66 14 patients with obstructive airways disease (1667 patient years of ex posure). Main outcome measures Proportions of patients who were: admit ted to hospital for respiratory diseases, reported adverse side effect s, or withdrew because of adverse affects. Results There were no signi ficant differences between the hydrofluoroalkane (HFA 134a) and chloro fluorocarbon inhaler groups in relation to the proportions of patients admitted to hospital for respiratory diseases (odds ratio 0.75; 95% c onfidence interval 0.51 to 1.08) or the proportions who reported adver se events (1.01; 0.88 to 1.17). However, more patients using the hydro fluoroalkane inhaler than the chlorofluorocarbon inhaler withdrew beca use of adverse events (3.8% and 0.9% respectively). Conclusion The hyd rofluoroalkane inhaler was as safe as the chlorofluorocarbon inhaler w hen judged by hospital admissions and adverse affects. The study desig n successfully fulfilled the recommendations of the guidelines. Differ ences between postmarketing surveillance studies and randomised clinic al trials in assessing safety were identified. These may lead to diffi culties in the design of postmarketing surveillance studies.