ABSTRACT
Digitalis and the cardiac glycosides increase the force of contraction of the myocardium. The various anticoagulant drugs are used medically to inhibit the clotting mechanism. Anticoagulant drugs are dangerous in blood dyscrasias; kidney, liver, or gastrointestinal diseases; hypertension; subacute infective endocarditis; and pregnancy. Administration of many other drugs enhances the effect of anticoagulants. Procainamide is used for the treatment of cardiac irregularities. Nitroglycerin, amyl nitrite, sodium nitrite, isosorbide mononitrate, and isosorbide dinitrate are used medically to dilate coronary vessels and to reduce blood pressure. The prothrombin concentration is lowered after coumarin and indandione anticoagulants. The clotting time is prolonged after heparin. Toxicity occurs as a result of the expected actions of the drugs and by interactions with other drugs used at the same time. Effects are as for acute poisoning plus gastrointestinal distress with nausea and constipation, skin rash, flushing, dependent edema, weakness, and dizziness.
