Pharmacist recognition of potential drug interactions

The ability of pharmacists to identify potential drug interactions was studied. Simulated medication profiles were created from a list of 16 drugs. Staff pharmacists and soon-to-graduate student pharmacists at a Veterans Affairs medical center each received a set of eight 2-drug profiles, four 4-drug profiles, two 8-drug profiles, and one 16-drug profile. Each set of profiles contained a number of pairs of drugs rated by the Drug Therapy Screening System as producing an interaction of moderate or major importance. The subjects were given one hour to screen the profile for the potentially interacting pairs. The subjects detected only 66% of the interactions in the 2-drug profiles, 34% of the interactions in the 4-drug profiles, 20% of the interactions in the 8-drug profiles, and 17% of the interactions in the 16-drug profile. None of the subjects detected all interactions in the 8- or 16-drug profiles. Both true-positive and false-positive rates of identification decreased significantly as the number of drugs listed on the profile increased. This primarily reflected a reduced tendency to report the presence of drug interactions, but there was additional evidence that the accuracy of identification also declined. The number of years of pharmacy training was the only demographic characteristic highly correlated with accuracy. More years of pharmacy education seemed to improve the ability to detect drug interactions. However, none of the pharmacists or students was able to detect all potentially interacting pairs in a profile containing 8 or 16 drugs. Computerized drug interaction profiles should be used by pharmacists to ensure recognition of all potential drug interactions.