Intended for healthcare professionals

Rapid response to:

Analysis

Controversy over generic substitution

BMJ 2010; 340 doi: https://doi.org/10.1136/bmj.c2548 (Published 01 June 2010) Cite this as: BMJ 2010;340:c2548

Rapid Response:

Generic Drugs

Further to the article by Ferner and colleagues I would like to
highlight the issue of within generic differences. Several patients who
self-manage their own oral anticoagulation have pointed out to me
clinically significant changes in their INR measurements depending upon
which generic brand of warfarin is dispensed. One of these patients went
as far as obtaining bioavailability data from different manufacturers. As
the decision as to which generic to dispense is based on price there is
potential to influence clinical outcome for patients by switching
products. This is a further, and previously unreported, variable which
makes managing patients taking oral anticoagulants so difficult.

Competing interests:
None declared

Competing interests: No competing interests

20 June 2010
David A Fitzmaurice
Professor of Primary Care
University of Birmingham, B15 2TT