Abstract
To assess the effects of oral contraceptives on anticoagulant treatment the prothrombin times of 12 patients were measured while they were taking both drugs simultaneously and while they were taking only anticoagulants. The mean prothrombin time ratio was significantly higher when patients were taking both drugs than when they were taking only anticoagulants and their doses of anticoagulant were significantly lower. During both periods most of the prothrombin values remained in the therapeutic range. These findings suggest that, contrary to the common belief that oral contraceptives diminish the effects of anticoagulants, contraceptives in fact potentiate the action of the anticoagulants.
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- Poller L. The British system for anticoagulant control. Thromb Diath Haemorrh. 1975 Apr 30;33(2):157–162. [PubMed] [Google Scholar]
- Poller L., Thomson J. M., Tabiowo A., Priest C. M. Progesterone oral contraception and blood coagulation. Br Med J. 1969 Mar 1;1(5643):554–556. doi: 10.1136/bmj.1.5643.554. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schrogie J. J., Solomon H. M., Zieve P. D. Effect of oral contraceptives on vitamin K-dependent clotting activity. Clin Pharmacol Ther. 1967 Sep-Oct;8(5):670–675. doi: 10.1002/cpt196785670. [DOI] [PubMed] [Google Scholar]
- Srinivasan S., Solash J., Redner A., Moser C., Farhangian D., Lucas T. R., Ateyeh E., Jr, McCool CT+MACCOOL C. T., Weber D., Puvan S. I. The alteration of surface charge characteristics of the vascular system by oral contraceptive steroids. Contraception. 1974 Mar;9(3):291–303. doi: 10.1016/0010-7824(74)90020-1. [DOI] [PubMed] [Google Scholar]
- Weser J. K., Sellers E. Drug interactions with coumarin anticoagulants. 2. N Engl J Med. 1971 Sep 2;285(10):547–558. doi: 10.1056/NEJM197109022851005. [DOI] [PubMed] [Google Scholar]