Danazol increases the anticoagulant effect of warfarin

Meeks ML, M. L. Meeks, K W Mahaffey, Mahaffey KW, Kenneth W. Mahaffey, Moshe Katz, M D Katz, Michael D. Katz, Katz MD
The Annals of pharmacotherapy · 1992 · vol. 26(5) , pp. 641–642 · doi:10.1177/106002809202600506 · PMID:1591422 · W2205634867
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Two cases and existing literature indicate that danazol potentiates warfarin's anticoagulant effect, potentially leading to bleeding complications through metabolic inhibition or direct effects on coagulation.

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Abstract

OBJECTIVE: To report two cases demonstrating an interaction between danazol and warfarin, resulting in the potentiation of warfarin's effect and bleeding complications. DATA SOURCES: Case reports, review articles, and studies identified by MEDLINE. STUDY SELECTION: All published English-language reports involving danazol and warfarin interactions were reviewed. DATA SYNTHESIS: Danazol, a synthetic testosterone derivative, is used in the treatment of endometriosis, fibrocystic breast disease, menorrhagia protein C deficiency, and hemophilia. We describe two cases including an interaction between danazol and warfarin, resulting in bleeding complications. There are at least two other reported cases of this interaction. This interaction may be attributable to several mechanisms. Danazol may inhibit the metabolism of warfarin and/or it may have a direct effect on the coagulation and fibrinolytic systems. CONCLUSIONS: Based on this report and other published cases, clinicians must be aware that danazol may increase the anticoagulant effect of warfarin. Patients receiving warfarin who are prescribed danazol must be monitored closely to prevent excessive anticoagulation and subsequent bleeding. Studies are needed to determine the frequency of this interaction and its underlying mechanisms.

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Condition tags

endometriosis

MeSH descriptors

Danazol Warfarin Adult Adult Cerebrovascular Disorders Cerebrovascular Disorders Cerebrovascular Disorders Danazol Danazol Danazol Drug Synergism Drug Synergism Female Female Humans Humans Middle Aged Middle Aged Prothrombin Time Prothrombin Time

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