SEMINAR on Drugs Used in Cardiac Disease

Seminar on drugs used in cardiac diseases Introduction Cardiovascular drugs encompass a large number of prescription medications that are used to control heart disease. It is a complicated group of drugs with many being used for multiple heart conditions. You may also encounter patients who have one or more cardiovascular conditions such as CHF, hypertension and an arrhythmia. These patients may be taking multiple medications for each condition. If you look at the list of Top 200 drugs, you will find that 25% of those drugs are cardiovascular drugs, which is another good reason to become familiar with these drugs and how they might interact with other medications.

CLASSIFICATION OF CARDIAC USED IN CARDIAC DISEASES

1. Anti-arrhythmic agent The arrhythmias are conceptually sirnple-dysfunctions cause abnormalities in impulse formation and conduction in the myocardium. However, in the clinic, arrhythmias present as a complex family of disorders that show a variety of symptoms. For example, cardiac arrhythmias may cause the heart  to beat too slowly (sinus bradycardia)  to beat too rapidly (sinus or ventricular tachycardia, atrial or ventricular premature depolarization, atrial flutter)  to respond to impulses originating from sites other than the SA node  to respond to impulses traveling along accessory (extra) pathways that lead to deviant depolarizations (A-V reentry, Wolff-Parkinson White syndrome). In order to make sense of this large group of disorders, it is useful to organize the arrhythmias into groups according to the anatomic site of the the abnormality-the atria, AV node, or the ventricles. Class of anti-arrhythmia drug Class 1 sodium channel blocker e.g. flecanide, quinidine Class 2 beta adrenoreceptor blocker e.g. metoprolol, propanolol Class 3 sodium channel blocker e.g. amiodarone Class 4 calcium blocker e.g. diltiazem, verapamil, nifedipine Other Anti-arrhythmic drug e.g. adenosine, digoxin

2. Anti-anginal drug Angina pectoris is a characteristic chest pain caused by coronary blood flow that is insufficient to meet the oxygen demands of the myocardium. The imbalance between oxygen delivery and utilization may result from a spasm of the vascular smooth muscle or from obstruction of blood vessels caused by atherosclerotic lesions. Angina is characterized by a sudden, severe pressing substernal pain radiating to the left arm.  Organic nitrates e.g. isosorbide dinitrate, nitroglycerin  Beta blocker e.g. propanolol  Calcium channel blocker e.g. diltiazem, verapamil, nifedipine

3. Drugs affecting blood  Platelet inhibitor e.g. aspirin, ticlopidine  Anticoagulant e.g. enoxaparin, warfarin, heparin.  Thrombolytic agent e.g. urokinase, streptokinase  Treatment of bleeding e.g. aminocaproic acid, vitamin k, tranexamic acid  Treatment of anemia e.g. folic acid, cyanocobalamine, iron

4. Antihypertensive drug Hypertension is defined as a sustained diastolic blood pressure greater than 90 mm Hg accompanied by an elevated systolic blood pressure (>I 40 mm Hg). Hypertension results from increased peripheral vascular smooth muscle tone, which leads to increased arteriolar resistance and reduced capacitance of the venous system. Elevated blood pressure is an extremely common disorder, Although hypertension may occur secondary to other disease processes, more than 90% of patients have essential hypertension, a disorder of unknown origin affecting the blood pressure-regulating mechanism. A family history of hypertension increases, the likelihood that an individual will develop hypertensive disease. Essential hypertension occurs four times more frequently among blacks than among whites, and it occurs more often aniong middle-aged males than among middle-aged females. Environmental factors such as a stressful lifestyle, high dietary intake of sodium, obesity, and smoking all further predispose an individual to the occurrence of hypertension.  Diuretics e.g. hydrochlorothiazide, frusemide, spirolactone  Alpha blocker e.g. doxazosin, prazosin  Beta blocker e.g. metoprolol, propanolol  ACE inhibitor e.g. catopril, analapril, ramipril  Angiotensin II antagonist e.g losartan  Calcium channel blocker e.g. diltiazem, verapamil, nifedipine, amlodipine

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Vasodilators e.g sodium nitropruside

5. Inotropic agents  Positive inotropic agent e.g. dobutamine  Negative inotropic agent e.g. dopaamine 6. Cardiac glycosides e.g. digoxin, digitoxin 7. Hypolipidemic agents e.g. statin

FLECANIDE Group of drug – antiarrhythmic agent, sodium channel blocker Pharmacological name- flecanide Trade name – Almarytm, Apocard, Ecrinal, Flécaine Dose of drug – 1-2.5mg/kg/body wt Route of drug - oral Action - Flecainide is is a class I C antiarrhythmic agent, Flecainide has local anesthetic activity and belongs to the membrane stabilizing (Class 1) group of antiarrhythmic agents; it has electrophysiologic effects characteristic of the IC class of antiarrhythmics, ntiarrhythmic actions are mediated through effects on sodium channels in Purkinje fibers. Flecainide is a sodium channel blocker, binding to voltage gated sodium channels. It stabilizes the neuronal membrane by inhibiting the ionic fluxes required for the initiation and conduction of impulses. Ventricular excitability is depressed and the stimulation threshold of the ventricle is increased during diastole. Indication: prevention of paroxysmal supraventricular tachycardias (PSVT), including atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia and other supraventricular tachycardias of unspecified mechanism associated with disablin Contraindication: hypersensitivity, cardiogenic shock, CHF, pre-existing sinus node dysfunction or 2nd or 3rd degree heart block (without a pacemaker), renal impairment, pregnancy, lactation or children. Adverse effect 

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Nausea and vomiting, convulsions, hypotension, bradycardia, syncope, extreme widening of the QRS complex, widening of the QT interval, widening of the PR interval, ventricular tachycardia, AV nodal block, asystole, bundle branch block, cardiac failure, and cardiac arrest. CNS – dizziness, anxiety, fatigue, headache, mental depressin. tremor, Blurred vision, Chest pain, CHF

Role and responsibility of nurse    

Monitor ECG may cause QRS widening, PR prolongation, QT prolongation Monitor intake and output, daily weigh the patient Asses for signs of CHF Monitor Blood pressure and pulse throughout the therapy

QUINIDINE Group of drug - antiarrhythmic agent (class 1 A), sodium channel blocker Pharmacological name–Quinidine Dose of drug–  PO (Adults): 324–972mg q 8–12 hr.  IV (Adults): 200–400 mg given at a rate