Anti Hypertensive Drugs

All Details regarding Anti Hypertensive drugs

1. ANTIHYPERTENSIVE DRUGS Presentation by - Diksha Kumari B.pharm 6 th sem 22 Gurunanak institute of pharmaceutical science and technology

2. Definition -Hypertension is common cardiovascular disease determined by increase blood pressure (pressure exerted by blood against the wall of a blood vessel )in arteries. Normal blood pressure- 120/80 mmHg systolic/diastolic Symptoms that may occur include : Confusion Ear noise or buzzing Fatigue Headache Irregular heartbeat Nosebleed Vision changes BP= CO X SVR BP = Blood pressure CO =Cardiac output SVR=Systemic vascular resistance

3. Category Systolic Blood Pressure( mmHg ) Diastolic Blood Pressure (mmHg) Pre-hypertension 120-139 80 Hypertension – Stage 1 140-159 90-99 Hypertension – Stage 2 160-179 100-109 Hypertension – Stage 3 > 180 > 110 CATEGORIES OF HYPERTENSION ACCORDING TO EUROPEAN SOCIETY OF CARDIOLOGY.

4. RISK FACTORS- Hyperlipidaemia –more LDL content Tension and stress Smoking-more nicotine intake Diabetes mellitus Imbalance between vasoconstrictor and vasodilators peptides

5. Treatment-Why???

6. Global Mortality 2000: Impact of hypertension and other health risk factors Adapted from Ezzati et al. Lancet 2002;360:1347–60 Attributable mortality (in millions (total: 55,861,000) Developing region Developed region 8 7 6 5 4 3 2 1 High BP Tobacco High cholesterol Unsafe sex High BMI Physical inactivity Alcohol Underweight

7. Antihypertensive Drug Therapy

8. DIURETICS : EXAMPLES: Thiazides: chlorthalidone High ceiling:Furosemide K+ sparing:Spironolactone , MOA : Act on V-2 receptor in kidneys (vasopressin receptor) having an antediuretic function---- leads to diuresis ----increased secretion of Na & H 2 O decrease in blood volume ----decreased CO----decreased BP. Adverse Reactions dizziness, electrolyte imbalance/depletion, hypokalemia , hyperlipidemia , hyperglycemia ( Thiazides ) Contraindications hypersensitivity, compromised kidney function hyponatremia

9. Central Sympatholytics ( a -2 Agonists) Drugs : clonidine , methyldopa Site of Action:CNS medullary ,cardiovascular centers MOA: CNS a-2 adrenergic stimulation---- autoinhibitory feed back mechanism----decreased sympathetic outflow----decreased norepinephrine release----vasodilatation----decreased PR---- decreased BP. Adverse Effect:dry mouth; sedation; drowsiness;nasal congestion SYMPATHOLYTIC DRUGS a -1 Adrenergic blockers (Antagonists) Drugs:Prazocin,Terazocin Site of Action: peripheral arterioles, smooth muscle MOA :Blocks a -1 receptor(in post synaptic neurone as well as in vascular smooth muscles)---- cause vasodialatation due to relaxation of vascular smooth muscles---- decreased PR----also reduces preload by pooling of blood----decreased CO ---- decreased BP. Adverse Effects:nausea ; drowsiness; postural hypotension ;headache

10. b - ADRNERGIC BLOCKERS(ANTAGONISTS) Drug s: Non Selective– Propranolol,Timolol, Pindolol Cardioselective – Atenolol , Metoprolol (acts only on beta-1 receptor ) Site of Action : heart,kidney . MOA: 1.heart:blocks b -1receptor---reduce heart rate ---- decreased CO---- decreased BP 2.kidney:decreased renin production(mediated by b - 1 receptor)----depresses RAS system---- decreased PR----decreased BP Advantages :No postural hypotension;No salt and water retention Low incidence of side effects Adverse Effects :impotence ; bradycardia ; fatigue; exercise intolerance Contraindication: asthma;bradycardia;hypersensitivity b-1 DUAL ALPHA & BETA RECEPTOR ANTAGONISTS Drugs : Labetalol (3:1 ratio of beta:alpha blocking activity), Carvedilol IT IS USEFUL IN HYPERTENSIVE EMERGENCIES VASODIALATOR Drugs : Arteriolar – Hydralazine Arterio-venular : Sodium Nitroprusside (USED IN EMERGENCY SITUATION) MOA: Releases NO ----stimulation of guanylyl cyclase ---- more conversion of GTP to cGMP -----activate protein kinase ----inhibit MLCK phosphorylation ---- myosin phosphorylation & combination with actin inhibited----relaxation of vascular smooth muscles---- vasodialatation .

11. CALCIUM CHANNEL BLOCKERS (CCBs) Drugs : verapamil ; nifedipine ; diltiazem ; amlodipine:felodipine Site of Action- Vascular smooth muscle K Ca Na MOA:Blocks long acting voltage sensitive calcinm channels Advantages: No sedation or other CNS effects Can be given to asthma patients & angina patients No impairment of renal perfusion No deleterious effect on uric acid level& electrolyte balance Side effects : flushing; headache; tachycardia; peripheral oedema gastroesophageal reflux Contraindications : Congestive heart failure; Pregnancy and lactation

12. DRUGS ACTING ON RENIN ANGIOTENSIN SYSTEM (RAS) 1ACE inhibitors: captopril;enalapril ; lisinopril 2 renin inhibitors: Aliskiren ; remikinen 3 AT1 receptor antagonists: losartan ; candesartan 1 st line of Drug: No postural hypotension or electrolyte imbalance (no fatigue or weakness) Safe in asthmatics and diabetics Prevention of secondary hyperaldosteronism and K+ loss Reverse the ventricular hypertrophy and increase in lumen size of vessel No hyperuraecemia or deleterious effect on plasma lipid profile Side effects: Dry cough; Steep fall in BP with 1 st dose Skin rash Angioneurotic oedema

13. Reference- 1)Essentials of medical pharmacology sixth edition K.D Tripathi MD 2010. Jaypee brothers medical publishers. Page no-539 to 554. 2)Introduction to pharmacology by S.K kulkarni updated seventh edition. Page no-286 to 302 THANK YOU