de Teresa E, Vera A, Ortigosa J, Pulpon L A, Arus A P, de Artaza M
Br Med J. 1979 Nov 17;2(6200):1260-1. doi: 10.1136/bmj.2.6200.1260.
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.
为评估口服避孕药对抗凝治疗的影响，对12名患者在同时服用两种药物时以及仅服用抗凝剂时的凝血酶原时间进行了测量。患者同时服用两种药物时的平均凝血酶原时间比值显著高于仅服用抗凝剂时，且其抗凝剂剂量显著更低。在两个阶段，大多数凝血酶原值都保持在治疗范围内。这些发现表明，与口服避孕药会削弱抗凝剂作用的普遍看法相反，避孕药实际上增强了抗凝剂的作用。
