title: Isosorbide dinitrate. Effect on the vasodilator response to nitroglycerin.
abstract: To evaluate whether there is cross-tolerance to the circulatory effects of isosorbide dinitrate and nitroglycerin, six subjects were given 120 mg/day of sustained-action isosorbide dinitrate in three divided doses for six to eight weeks. Prior to and during the last week of long-term isosorbide dinitrate administration, the effects of sublingually given nitroglycerin (0.9 mg) on plethysmographically measured calf blood flow and venous volume at 30 mm Hg (VV[30]) were measured on three occasions and averaged. Although the arteriolar dilation produced by nitroglycerin was unaltered by isosorbide dinitrate, the venodilation was significantly attenuated. The VV[30] increased from 3.00 to 3.28 ml/100 ml (P less than .02) with nitroglycerin prior to isosorbide dinitrate administration, but failed to increase with nitroglycerin during the long-term administration of isosorbide dinitrate (2.95 to 2.95 ml/100 ml, P greater than .5).
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001158:Arteries / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D001810:Blood Volume / Q000187:drug effects; D004347:Drug Interactions; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007269:Injections, Intra-Arterial; D007548:Isosorbide Dinitrate / Q000008:administration & dosage / Q000494:pharmacology*; D007866:Leg / Q000098:blood supply; D008875:Middle Aged; D005996:Nitroglycerin / Q000008:administration & dosage / Q000494:pharmacology*; D010646:Phentolamine / Q000008:administration & dosage / Q000494:pharmacology; D014655:Vascular Resistance / Q000187:drug effects; D014680:Veins / Q000187:drug effects
chemical_list: D005996:Nitroglycerin; D007548:Isosorbide Dinitrate; D010646:Phentolamine