Category: 03. Cardiovascular-Renal Drugs

Digoxin causes shortening of the atrial refractory period with small doses (vagal action) and a prolongation with the larger doses (direct action). It prolongs the effective refractory period of node directly and through the vagus. This action is of major importance in slowing the rapid ventricular rate in patients with atrial fibrillation Diuretics Diuretics are…

Verapamil: this drug acts by blocking the movement of calcium ions through the channels. It is absolutely contraindicated in patients on beta blockers, quinidine or disopyramide. It is the drug of choice in case of paroxysmal supraventricular tachycardia for rapid conversion to sinus rhythm.

AMIODARONE: This drug is used in the treatment of refractory supraventriculat tachyarrhythmias and ventricular tachyarrhythmias. It depresses sinus, atrial and A.V nodal function. The main adverse effects of this drug are anorexia, nausea, abdominal pain, tremor, hallucinations, peripheral neuropathy, A.V. block.

Propranolol: Myocardiac sympathetic beta receptor stimulation increases automaticity, enhances A.V. conduction velocity and shortens the refractory period. Propranolol can reverse these effects. Beta blockers may potentiate the negative inotropic action of other antiarrhythmics. Therapeutic uses: This is useful in tachyarrhythmias, in pheochromocytoma and in thyrotoxicosis crisis. It is also useful in patients with atrial fibrillation…

Quinidine: It blocks sodium channel so that there is an increase in threshold for excitability. It is well absorbed orally Adverse effects: It has low therapeutic ratio. Main adverse effects are SA block, cinchonism, severe headache, diplopia and photophobia. Lidocaine, which is used commonly as a local anaesthetic blocks both open and inactivated sodium channel…

Electrophysiology of cardiac muscle: the pathophysiological mechanisms responsible for the genesis of cardiac arrhythmias are not clearly understood. However, it is generally accepted that cardiac arrhythmias arise as the result of either of Disorders of impulse formation and/ or Disorders of impulse conduction. Pharmacotherapy of cardiac arrhythmias Antiarrhythmic drugs are used to prevent or correct…

Organic nitrates e.g. nitro-glycerine, isosorbide dinitrate, etc. Beta adrenergic blocking agents e.g. propranolol, atenolol, etc. Calcium channel blocking agents e.g. verapamil, nifedipine, etc. Miscellaneous drugs e.g. aspirin, heparin, dipyridamole. Organic nitrates: organic nitrates are potent vasodilators and successfully used in therapy of angina pectoris for over 100 years. The effects of nitrates are mediated through…

Congestive heart failure occurs when there is an inability of the heart to maintain a cardiac out put sufficient to meet the requirements of the metabolising tissues. Heart failure is usually caused by one of the following: Ischaemic heart disease, Hypertension, Heart muscle disorders, and Valvular heart disease. Drugs used to treat heart failure can…

a.    General consideration:- Hypertension is defined as an elevation of arterial blood pressure above an arbitrarily defined normal value. The American Heart Association defines hypertension as arterial blood pressure higher than 140/90mmHg (based on three measurements at different times). Hypertension may be classified in to three categories, according to the level of diastolic blood pressure:…

In the past decades, cardiovascular diseases were considered as major health problems mainly for western countries. However, the problem of cardiovascular disorders is also increasing in developing countries including Ethiopia. The most commonly encountered cardiovascular disorders include hypertension, congestive heart failure, angina pectoris and cardiac arrhythmias. Most drugs available currently are able to reduce the…