Copyright 2011 American Medical Association. All Rights Reserved. Applicable FARS/DFARS Restrictions Apply to Government Use.2011
Dr Horn is indeed correct that most of the alerts in our study were triggered by warfarin being prescribed to patients who already were receiving trimethoprim-sulfamethoxazole. Some of this was due to warfarin being prescribed 3 times more commonly than trimethoprim-sulfamethoxazole, as noted in our article.1 Dr Horn points out that dose titration of the warfarin might have allowed it to be used safely in patients already receiving trimethoprim-sulfamethoxazole. However, such patients might then be at risk of underanticoagulation when stopping therapy with trimethoprim-sulfamethoxazole, in most cases after being discharged from the hospital.
Strom BL, Schinnar R, Aberra F, Bilker W, Hennessy S, Leonard CE. Hard-Stops for Drug Interactions—Reply. Arch Intern Med. 2011;171(7):702-710. doi:10.1001/archinternmed.2011.110