A post-marketing surveillance study of formoterol (Foradil): its use in general practice in England

At the time of marketing, experience of long-term use of prescription medicines in general clinical practice is limited. Postmarketing surveillance is particularly important at this time when medicines may be prescribed to large numbers of patients of all ages, for long-term use. Following marketing of formoterol (Foradil) in the UK in 1996 we undertook a postmarketing surveillance study of formoterol use in general practice.

A non-interventional observational cohort study was conducted using the technique of prescription-event monitoring. Exposure data were obtained from prescription details; outcome data from questionnaires sent to general practitioners approximately 12 months after the first prescription was dispensed for individual patients. Incidence rates were calculated for reported events, reasons for stopping treatment and outcomes of pregnancy were determined.

Data were collected for 5777 patients aged 3 to 96 years, 65% of whom continued treatment for >12 months. Formoterol was prescribed 'off label', to 258 children, (4.5%) of the cohort. The most commonly reported events excluding those related to respiratory disease, were headache, tremor, palpitation, cramp and nausea/vomiting. These events were also among the more common reasons for stopping treatment and reported as suspected adverse drug reactions. 33 patients took formoterol during pregnancy. The cause of death was established for 186 of the 190 deaths (3% of cohort).

Formoterol appears to have been well tolerated by the majority of patients in this study. The most frequently reported adverse events were those known to be associated with beta(2)-agonists, although the frequency of nausea/ vomiting was greater than given in Summary of Product Characteristics.