title: Possible mechanism of the synergistic effect of heparin and dihydroergotamine.
abstract: A combination of heparin and dihydroergotamine mesylate (Heparin-Dihydergot) has been shown to be more effective than either of these drugs alone in preventing postoperative venous thromboembolism. The possible mechanism for the synergistic effect of heparin and dihydroergotamine was assessed. Phlebograms obtained after administration of 0.5 mg of dihydroergotamine showed marked constriction of the tibial and soleal veins with a significant reduction in the mean diameter of the femoral vein. The effect on the coagulation mechanism was assessed in 28 patients. Blood samples were withdrawn from the femoral vein during varicose vein operations. A significant difference was observed in antithrombin III activity, kaolin-cephalin clotting time, beta-thromboglobulin, and fibrino-peptide levels between the control, dihydroergotamine, heparin, and the combination groups.
mesh_terms: D000990:Antithrombin III / Q000032:analysis; D001777:Blood Coagulation / Q000187:drug effects; D001780:Blood Coagulation Tests; D001792:Blood Platelets / Q000187:drug effects; D004087:Dihydroergotamine / Q000494:pharmacology / Q000627:therapeutic use*; D004338:Drug Combinations / Q000627:therapeutic use; D004357:Drug Synergism; D005268:Femoral Vein / Q000187:drug effects; D006493:Heparin / Q000494:pharmacology / Q000627:therapeutic use*; D006495:Heparin, Low-Molecular-Weight; D006801:Humans; D008854:Microscopy, Electron; D013924:Thrombophlebitis / Q000517:prevention & control*; D014661:Vasoconstriction / Q000187:drug effects
chemical_list: D004338:Drug Combinations; D006495:Heparin, Low-Molecular-Weight; C031388:heparin-dihydergot; D004087:Dihydroergotamine; D000990:Antithrombin III; D006493:Heparin