The development of modified release oral dosage forms (retard dosage forms) is one of the main goals of pharmaceutical industry for drugs having a short half-life. The rationale of these dosage forms would be the reduction of interdose fluctuations throughout 24 hours owing to the decreased number of daily administrations. Consequently, the incidence of side effects is reduced and the patient compliance is improved. The drug prescription both in conventional and in retard dosage forms has been analysed in order to evaluate the impact of modified release dosage forms over the period from January 1990 to July 1993. As the analysis of the prescriptions shows, the consumption of the retard dosage forms is regularly increased. Usually, the preference toward retard dosage forms is different according to the drug and does not appear affected by the cost of the therapy
