• angiotensin receptor blocker;
  • drug utilization analysis;
  • managed care;
  • managerial experiment;
  • prior authorization


• The utility of a prior authorization (PA) requirement for curtailing the prescription of expensive drugs and improving quality of care has been well substantiated. Although studies have evaluated changes in prescribing behaviour after revocation of a PA requirement, the effectiveness of selective revocation for the first drug within a class to go off patent as an incentive to reduce prescription of the more expensive drugs has not been studied.


• Rescinding the PA requirement for a generic drug alone within a pharmacological category upon its introduction into the market is a successful managerial strategy for reduction of prescription of the more expensive drugs still on patent in that class. The observed duration of effect was approximately 1 year.

AIMS To evaluate whether rescinding the prior authorization (PA) requirement (managerial pre-approval) for losartan in an health maintenance organization (HMO) could reduce prescribing of the more expensive angiotensin receptor blockers (ARBs).

METHODS HMO physicians were notified that losartan would no longer require PA, and appropriate changes were made to the electronic prescribing computer program. The monthly distribution by drug of the number of prescriptions for ARBs dispensed for new patients was calculated before and after the policy change from data captured from electronic records. The proportion of patients (percentage and 95% confidence interval) treated with losartan who met the criteria for treatment with ARBs (hypertension or cardiac insufficiency in patients who have developed adverse effects in response to angiotensin-converting enzyme inhibitors or macroproteinuria) during the first month after the PA requirement was rescinded was calculated.

RESULTS The total number of PA requests for ARBs declined by 48.6% from 961 in December 2008, the month before the policy change, to 494 the following January, rising again to 651 during January 2010. Prescription incidence changed from 121 to 255 patients treated per month (114% increase) for losartan, from 15 to 16 (6.7% increase) for candesartan, and from 89 to 71 (20.2% decrease) for valsartan. The duration of effect for decrease in ARB requests for the more expensive drugs was approximately 1 year. Only 23.3% (95% confidence interval 18.1–28.4) of patients receiving losartan met the criteria for receiving ARBs.

CONCLUSIONS Rescinding the PA requirement for this drug alone was an effective limited-duration strategy for reduction of prescription of relatively expensive drugs.