Epidemiology of adverse reactions to carbamazepine as seen in a spontaneous reporting system

A survey was made of 505 reports on 713 adverse reactions to carbamazepine submitted to the Swedish Adverse Drug Reactions Advisory Committee from 1965-1987. For the period after 1972, the relation between the reports and sales statistics could be investigated. The total incidence of reported adverse reactions to carbamazepine was 4.5 per million defined daily doses (DDD), corresponding to 2.7 per million prescribed daily doses (PDD). Most often reported were skin reactions (48%), but reports on haematological (12%) and hepatic disorders (10%) were also frequent. Virtually all hepatic disorders and severe skin reactions, as well as the majority (60%) of the haematological reactions, occurred within the first 2 months of treatment. In view of the very low incidence of reported serious blood dyscrasias, such as pancytopenia (0.04/million PDD) and agranulocytosis (0.06/million PDD), continuous haematological monitoring seems to be of little value. The elderly appear to be at increased risk of developing blood dyscrasias and liver reactions, and alcohol abusers seem to represent a high-risk group for developing serious skin reactions.