Prescription monitoring of drug dosages in the county of Jämtland and Sweden as a whole in 1976, 1982 and 1985.

Prescribed doses of drugs for which individualisation of dosage is deemed necessary were recorded from one national and one local Swedish prescription monitoring study for the years 1976, 1982 and 1985. Dose patterns were analysed in order to determine whether the practice of individualising drug doses had become more widely adopted by physicians. Amongst drugs eliminated primarily by metabolism, (propranolol and amitriptyline were prescribed in highly variable doses (30-fold or more). The three commonest doses of these agents accounted for about 60% of the prescriptions. In general, doses decreased with increasing patient age. Prescribing practices for piroxicam differed markedly from those of propranolol and amitriptyline, with one fixed dose of piroxicam accounting for about 90% of all prescriptions. For drugs eliminated mainly by renal excretion (digoxin, cimetidine and atenolol) there was an 8-10-fold variation in the prescribed doses. The most frequent dose of these drugs accounted for 40-60% of the prescriptions. Doses of cimetidine and atenolol were lowered only in the oldest patients. The doses of digoxin decreased more evenly with increasing age, and were reduced in elderly patients on long-term maintenance therapy. The difference in digoxin dose between young and old patients increased during the study period. Prescription monitoring as a method for following-up drug usage may be instrumental in evaluating the effect of drug educational efforts.