OBJECTIVES. The authors compare the extent and nature of triazolam use
before and after its deletion from a health maintenance organization'
s (HMO) open and advisory-type drug formulary. METHODS. Benzodiazepine
dispensings of HMO members were collected for the 3 years before (198
9-1991) and for the 2 years after (1992-1993) the deletion of triazola
m from the HMO's drug formulary. The number of triazolam users, their
sex and ages, total annual exposure, estimated daily doses, and total
days of annual exposure were calculated and compared before and after
its deletion from the formulary. RESULTS. From being the most frequent
ly dispensed short-acting benzodiazepine in the HMO in 1989, the presc
ribing and use of triazolam decreased tenfold by the end of 1993. The
effect on who was using the drug and how it was being used was less dr
amatic. The elderly were frequent longterm users and had the longest e
xposure to the drug. CONCLUSIONS. An open and advisory-type formulary
can affect providers' drug selection behavior.