No Adverse Effects of Generic Warfarin, but Major Cost Savings


October 24, 2006 (Toronto, ON) - Substitution of generic warfarin for brand-name warfarin (Coumadin, Bristol-Myers Squibb) has no appreciable effect on rates of INR testing or hospitalization for adverse events, a new analysis suggests. In a research letter appearing in the October 25, 2006 issue of the Journal of the American Medical Association, J Michael Paterson and colleagues report that switching to either Apo-warfarin or Taro-warfarin was also associated with significant cost savings.

As the authors note, the provincial drug benefit plan in Ontario, Canada instituted a policy requiring pharmacists to switch to generic warfarin on June 7, 2001, with physicians being notified of the change one week beforehand. To track whether the switch had health or cost implications, Paterson et al examined all warfarin prescriptions in the 40 months before the policy was put in place, during the month in which the policy came into effect, and in the nine months following the implementation of the policy. They also checked for drugs that might affect outcomes in patients also taking warfarin.

In an interview with heartwire, Paterson said it was a matter of routine that the switch to generic warfarin would be evaluated. "This was part of a predefined study that was recommended in follow-up to the implementation of the policy after Ontario's expert drug committee recommended that the generic warfarin product be deemed interchangeable with Coumadin," he said.

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