title: A clinical and in vitro study on the possible interaction of intravenous nitrates with heparin anticoagulation.
abstract: It has been reported that intravenous nitrates inhibit the anticoagulant effect of heparin. This possible interaction has potentially serious implications for the management of patients with acute coronary ischemic syndromes. This possible interaction was assessed prospectively in a clinical and in an in vitro study involving 24 patients receiving both drugs for the management of unstable angina pectoris. There was a small inhibitory effect of intravenous glyceryl trinitrate or isosorbide dinitrate on the anticoagulant effect of heparin in 3 of 24 cases in vivo, as assessed by activated partial thromboplastin time measurements. Nitrates or propylene glycol had no effect on heparin activity in vitro. It was concluded that there may be an inhibitory effect of nitrates on anticoagulation in a small minority of patients, but close attention to detail in monitoring heparin anticoagulation is far more important.
authors.affiliation: Department of Medical Cardiology, Royal Infirmary, Glasgow, Scotland.
authors.forename: M
authors.initials: M
authors.lastname: Pye
authors.forename: K G
authors.initials: KG
authors.lastname: Oldroyd
authors.forename: J A
authors.initials: JA
authors.lastname: Conkie
authors.forename: I
authors.initials: I
authors.lastname: Hutton
authors.forename: S M
authors.initials: SM
authors.lastname: Cobbe
mesh_terms: D000789:Angina, Unstable / Q000188:drug therapy*; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D005260:Female; D006493:Heparin / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D066298:In Vitro Techniques; D007262:Infusions, Intravenous; D007548:Isosorbide Dinitrate / Q000008:administration & dosage / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009566:Nitrates / Q000008:administration & dosage / Q000627:therapeutic use*; D005996:Nitroglycerin / Q000008:administration & dosage / Q000627:therapeutic use; D010314:Partial Thromboplastin Time; D011446:Prospective Studies
chemical_list: D009566:Nitrates; D006493:Heparin; D005996:Nitroglycerin; D007548:Isosorbide Dinitrate