The ability of pharmacists to identify potential drug interactions was stud
ied.
Simulated medication profiles were created from a list of 16 drugs. Staff p
harmacists and soon-to-graduate student pharmacists at a Veterans Affairs m
edical center each received a set of eight 2-drug profiles, four 4-drug pro
files, two 8-drug profiles, and one 16-drug profile. Each set of profiles c
ontained a number of pairs of drugs rated by the Drug Therapy Screening Sys
tem 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 th
e 2-drug profiles, 34% of the interactions in the 4-drug profiles, 20% of t
he 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- o
r 16-drug profiles. Both true-positive and false-positive rates of identifi
cation decreased significantly as the number of drugs listed on the profile
increased. This primarily reflected a reduced tendency to report the prese
nce of drug interactions, but there was additional evidence that the accura
cy of identification also declined. The number of years of pha!rmacy traini
ng was the only demographic characteristic highly correlated with accuracy.
More years of pharmacy education seemed to improve the ability to detect dr
ug interactions. However, none of the pharmacists or students was able to d
etect all potentially interacting pairs in a profile containing 8 or 16 dru
gs. Computerized drug interaction profiles should be used by pharmacists to
ensure recognition of all potential drug interactions.