Antiplatelet drugs

Antiplatelet drugs – It is very useful in the treatment of severe hyperlipoproteinemia (HLP) and familial hypercholesterolaemia (F-HC) in whom satisfactory plasma levels of LDL-C are not achieved with single drug.

The most commonly used antiplatelet drugs is aspirin. It is used chronically in very low doses (40 to 325 mg per day) to prevent cardiovascular and cerebrovascular events. It irreversibly decreases platelet aggregation and consequently increases the bleeding time. At these doses, anticipated effect will have little impact on bleeding after oral surgical procedures.

However, if the patient has other underlying medical conditions that predispose to impaired homeostasis (such as uremia or liver disease), takes other antiplatelet drugs (including non-aspirin NSAIDs) or abuses alcohol, aspirin should be discontinued 3 to 7 days prior to surgery.

If emergency surgery needs to be performed and the patient’s bleeding time is higher than 15 to 20 minutes, 1- desamino-8-D-arginine vasopressin (DDAVP) can be used to improve haemostasis within 1 hour of surgery.

Antiplatelet drugs are more useful in the prevention of arterial thrombosis.

Aspirin with/without dipyridamol is used to prevent arterial thrombosis in high risk patients and during coronary artery bypass as well as to prevent attacks of secondary myocardial infarction.

To prevent arterial thrombosis, aspirin is used during haemodialysis and aspirin + warfarin is employed after using prosthetic heart valve.

To treat acute myocardial infarction fibrinolytic therapy is started within 6 hours which is followed by aspirin with/without dipyridamol.

Fibrinolytic therapy is also indicated in acute peripheral arterial thrombosis antiplatelet drugs.

Aminocaproic acid and tranxamic acid inhibit activation of plasminogen to plasmin which breaks down fibrin in vivo.

Nicotinic acid, fibrates (clofibrate, gemfibrozil, benzafibrate), guggulipid, and omega-3-marine triglycerides primarily decrease plasma triglycerides.

Anion exchange resins, neomycin, betasitosterols, statins, probucol, dthyroxine primarily reduce plasma cholesterol, antiplatelet drugs.

Since low density lipoproteins and very low density lipoproteins are both raised and single agent is ineffective in reducing low density lipoproteins, drug combinations are used in hyperlipidaemia, e.g. bile acid binding resin + fibrates to treat familial combined hyperlipaedimia; bile acid-binding resin + niacin to treat familial hypercholesterolaemia and familial combined hyperlipidaemia; bile acid-binding resin+statin to treat familial hypercholesterolaemia; and niacin + statin + bile acid-binding resin to treat patients with severe disorders involving elevated low density lipoproteins levels.

To correct hypovolemia in shock, either whole blood and plasma or plasma antiplatelet drugs are used as quickly as possible to avoid generalized impairment of cellular function.

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