AntiHPN-Beta and Calcium Blockers PDF

NCM 235 Drugs Acting on the cardiovascular system  NCM 235 Beta adrenergic Blockers Click here  Beta Adrenergic Blockers Non selective: Cardioselective: propranolol metoprolol atenolol nadolol esmolol, timol...

NCM 235 Drugs Acting on the cardiovascular system  NCM 235 Beta adrenergic Blockers Click here  Beta Adrenergic Blockers Non selective: Cardioselective: propranolol metoprolol atenolol nadolol esmolol, timolol betaxolol pindolol labetolol carvedilol  Beta Adrenergic Blockers All beta-blockers have similar antihypertensive effects irrespective of additional properties Inhibit the secretion of renin and the formation of angiotensin I Therapeutic applications: decreases cardiac workload and can ease the symptoms of angina pectoris. By slowing conduction through the mycardium, they treat dysrhythmias. They are also included in the treatment of heart failure, MI and migraine.  Non Cardiovascular Uses Migraine In anxiety provoking situations Glaucoma Hyperthyroidism Pheocromocytoma Alcohol withdrawal Oesophageal varices Advantages of Beta Blockers 1. No postural hypotension 2. No salt and water retention 3. Low incidence of side effects 4. Low cost 5. Once a day regimen 6. Preferred in young non-obese patients, prevention of sudden cardiac death in post infarction patients and progression of CHF Side effects: Fatigue, lethargy or decreased work capacity Loss of libido or impotence Cognitive defects like forgetfulness Adverse effects Bronchoconstriction Bradycardia Cold extremeties CNS side effects Heart Failure Hypoglycemia Rebound hypertension Advantages of cardio-selective over non- selective: Safe for use in  Asthma  Diabetes mellitus  Peripheral vascular disease Preferred in young non-obese hypertensive Angina pectoris and post angina patients Post MI patients – useful in preventing mortality In old persons, carvedilol, which has a vasodilatory action can be given NCM 235 ALPHA adrenergic Blockers  Alpha Adrenergic Blockers Lowers BP directly by blocking the sympathetic receptor in arterioles causing the vessels to dilate Not the first-line drugs for HTN because long-term clinical trials have shown them to be less effective at reducing the incidence of serious cardiovascular events than diuretics.  Non selective alpha blockers like phenoxybenzamine and phentolamine are not used in chronic essential hypertension but only in pheochromocytoma (vascular tumor of chromaffin tissue of the adrenal medulla). Specific alpha-1 blockers like prazosin, terazosin and doxazosine are used in chronic essential hypertension Tamsulosin is effective against benign prostatic hypertrophy (BPH) Therapeutic Uses: Reduction in mean BP Does not produce tachycardia since presynaptic auto or alpha-2 receptors are not inhibited Autoregulation of Na+ release remains intact Adverse effects: Prazosin causes postural hypotension so start with 0.5 mg at bed time with increasing dose and up to 10 mg daily Fluid retention in monotherapy Headache, dry mouth, weakness, blurred vision, rash, drowsiness and failure of ejaculation in males Current status: Improvement of carbohydrate metabolism so beneficial for diabetics since it lowers LDL and increases HDL Not used as first line agent Used in addition with other conventional drugs which are failing such as diuretic or beta blocker Other example: Minipress Prazopress NCM 235 Calcium Channel Blockers In a nutshell: Prevent the movement of calcium into the cardiac and smooth muscle cells when the cells are stimulated Blocking of calcium interferes with the muscle cell’s ability to contract, leading to a loss of smooth muscle tone, vasodilation, and a decrease in peripheral resistance Calcium channel blockers are effective in the treatment of angina Examples of Calcium Channel Blockers available in the Philippines: Amlodipine (Norvasc) Felodipine (Plendil ER) Nifedipine ( Adalat, Calcibloc) Diltiazem ( Dilzem) Nicardipine (Cardepine) Potential Side Effects: Dizziness or lightheadedness Low blood pressure Heart rhythm problems Dry mouth Edema (swelling of ankles, feet, or lower legs) Headache Potential Side Effects: Nausea Fatigue Skin rash Constipation or diarrhea Gastroesophageal reflux disease Advantages: Unlike with diuretics, there is no adverse metabolic effects but mild adverse effects like dizziness, fatigue, etc. No sedation or CNS effect Can be given to asthma, angina and PVD patients No renal and male sexual function impairment No adverse fetal effects and can be given in pregnancy Minimal effect on quality of life  CCBs are not 1st line of antihypertensive unless indicated but rather the use of ACE Inhibitors/diuretics/beta blockers. However it is been used because of excellent tolerability and high efficacy Preferred in elderly because it prevents stroke They are next to ACE inhibitors in inhibition of albuminuria and prevention of diabetic nephropathy Interact with grapefruit juice causing an increase level of calcium channel blockers to toxic dose  For a comprehensive discussion of CCBs Go to this link: https:// www.youtube.com/watch? v=pF55q5fqAP4