Topical corticosteroid prescribing patterns following changes in drug benefit status. 
To examine changes in prescribing patterns for topical corticosteroid products dispensed to elderly patients in Nova Scotia, Canada, after all but 2 combination topical corticosteroid products were removed from the Nova Scotia Seniors' Pharmacare Program benefit list.  Administrative prescription claims from the Nova Scotia Seniors' Pharmacare Program were used to identify the number and costs of topical corticosteroid, antifungal, antibiotic, and combination corticosteroid products dispensed.  Time-series analysis was used to compare the periods before (April 1, 1999-March 31, 2000) and after (April 1, 2000-March 31, 2001) the delisting.  In 1999-2000, 26,031 of 103 400 eligible elderly patients (25%) and in 2000-2001, 22,837 of 95,550 eligible elderly (24%) received a prescription for a defined topical product.  Nova Scotia Seniors' Pharmacare Program expenditures for all topical products decreased from 11.88 to 10.60 Canadian dollars per beneficiary per year (11%) after the policy revision.  Topical combination products decreased from 18% of all topical products dispensed to 14%, while the percentage of potent corticosteroid products dispensed increased from 24% to 27% over the study period.  Pre- and post-policy time-trend analysis showed statistically significant increasing trends in cost per beneficiary for all topical products and potent corticosteroid products.  Combination corticosteroid products showed no change in trends for costs per beneficiary before, and a slight increasing trend after, the policy revision.  Prescribing of topical corticosteroid combination products in Nova Scotia decreased following the formulary revision.  There was an increase in potent topical corticosteroid prescribing.  Future study involving evaluation of patient outcomes would be useful.