Evaluation of adverse drug event information in US manufacturer labels.

Pharmaceutical manufacturer labels are an important source of adverse drug event (ADE) information. The study objective was to determine the sufficiency of ADE reporting in US drug labels. A sample of 50 labels was evaluated from the top 200 drugs dispensed in the US. Electronic copies of labels were obtained and reviewed by 2 pharmacists for ADE incidence and discontinuation data. ADE incidence data were provided in 86% of labels. However, discontinuation rates due to ADEs and ADE incidence by dose were only reported in 60%. ADE incidence reporting by age (46%) or gender (18%) was also low. ADEs that occurred in less than 2% of the population were rarely reported. Incidence rates were based on small populations (median of 794) and short term studies (median of 84 days for chronic conditions). Labels for 19 drugs used chronically had no long term study data. Methods for collecting ADE data were stated in only 12% of labels. Adverse drug event and drug discontinuation data is under-reported in US labels. More information on adverse events causing discontinuation (especially serious events) and those related to dose, age, and gender is needed in labels to ensure safe prescribing and dispensing of drugs.