Hereditary resistance to oral anticoagulants: a case report.

Resistance to vitamin K antagonists is a rare phenomenon. In general, it is the result of poor patient compliance, malabsorption, a diet rich in vitam in K, or the use of enzyme inducers. Occasionally, the diagnosis of resista nce is made when plasma levels are high. The authors report a case of hereditary resistance to vitamin K antagonists in a 43 year old man admitted for atrial fibrillation. The precise prevale nce of this anomaly is unknown. However, the existence should be known to c linicians who often use this important family of drugs.