A retrospective, observational survey, conducted under the remit of the Safety Assessment of Marketed Medicines guidelines, collected data on nearly 1100 patients who had attempted an opiate detoxification with lofexidine, to identify current treatment protocols and safety. This approach offered a number of advantages over a prospective, randomized, clinical trial. It captured data on 'real-life' patients with a variety of co-existing illnesses and taking a wide range of concurrent medications. Data on exposure to lofexidine by three pregnant patients were documented and different dosage regimens have been described. The retrospective approach was not, however, without some limitations. The patients' medical notes were found to be incomplete and causality had not been assigned for many of the adverse events. However, providing the limitations of the retrospective approach are acknowledged, useful information has been collected on the current usage and safety of lofexidine, which has enabled the manufacturer to make a number of recommendations. Copyright (c) 2000 John Wiley & Sons, Ltd.