Inhibition of phenprocoumon anticoagulation by carbamazepine.
Carbamazepine inhibits warfarin and dicoumarol anticoagulation through induction of cytochrome P450-enzymes. Inhibition of phenprocoumon anticoagulation by carbamazepine has been supposed in some reviews, however, without hard empirical evidence. We report a patient who was anticoagulated with phenprocoumon in whom carbamazepine produced a dramatic increase in prothrombin time ratio (Quick). After discontinuation of carbamazepine, Quick-values returned to therapeutic levels. Valproate did not affect phenprocoumol's anticoagulant properties. The potentially hazardous carbamazepine-phenprocoumon interaction should be emphasized in reference drug manuals.
Schlienger
R
R
Division of Clinical Pharmacology, Department of Internal Medicine, University Hospital, Basel, Switzerland.
Kurmann
M
M
Drewe
J
J
Müller-Spahn
F
F
Seifritz
E
E
D000925:Anticoagulants / Q000627:therapeutic use; D018692:Antimanic Agents / Q000627:therapeutic use*; D002220:Carbamazepine / Q000627:therapeutic use*; D004347:Drug Interactions; D019263:Dysthymic Disorder / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008875:Middle Aged; D010644:Phenprocoumon / Q000627:therapeutic use; D011517:Prothrombin Time; D020246:Venous Thrombosis / Q000188:drug therapy
D000925:Anticoagulants; D018692:Antimanic Agents; D002220:Carbamazepine; D010644:Phenprocoumon