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B blockers
This document summarizes beta blockers, including their mechanism of action, classification, properties, uses, adverse effects and drug interactions. Beta blockers work by blocking beta receptors and inhibiting the adrenergic response. They are classified as first, second or third generation, and can be selective for beta 1 receptors or non-selective. Common uses include hypertension, angina, arrhythmias, migraine prophylaxis and anxiety. Side effects include bradycardia, bronchospasm and hypoglycemia. Drug interactions can occur pharmacokinetically or pharmacodynamically with drugs like digoxin. Overdose treatment involves atropine, pacing and glucagon administration.
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B blockers
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- 3. BETA BLOCKERS Drugs whichinhibit adrenergic response mediated by beta receptors
- 4. BETA RECEPTORS Receptors Sitesactions β1 Heart JG cells-kidney Posterior pituitary Adipose tissue stimulatory Renin release ADH release lipolysis β2 Bronchi Blood vessels of skeletal muscle Smooth muscle (Uterus ,intestine , detrusor) Liver, Muscle Adipose tissue Eye Bronchodilation Vasodilatation Relaxation Glycogenolysis Lipolysis Enhanced aqueous secretion β3 Adipose tissue Lipolysis
- 5. Professor Raymond PAhlquist Classified adrenoreceptors. (1948)
- 6. HISTORY 1st β blocker–DICHLORO ISOPROTERENOL-1958 PRONETHALOL---1962 PROPRANOLOL--1963 NEWER β BLOCKERS James Black
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- 8. MECHANISM OF ACTION ViaGPCR Antagonist binding to receptor No stimulation of G protein No change in cAMP conc No EFFECT
- 9. PROPERTIES Receptor Blockade Nonselective βblockade Selective β1 blockade Β+α blockade Intrinsic sympathomimetic property-ISA (partial agonistic action) Membrane stabilising action-MSA (Local anaesthetic action-Na channel block)
- 10. CLASSIFICATION Beta blockers 1st generation Classical Non selective 2nd generation Classical Beta 1 selective 3rdgeneration Newer Non selective & beta1 selective + Add. properties
- 11. 1ST GENERATION –NON SELECTIVE With ISA only Penbutolol With MSA only Propranolol With ISA & MSA Pindolol Without ISA &MSA Timolol Nadolol Sotalol
- 12. 2ND GENERATION –SELECTIVE Β1 AGENTS With MSA only Metoprolol With ISA & MSA Acebutolol Without ISA &MSA Atenolol Bisoprolol Esmolol
- 13. 3RD GENERATION Non-selective Selective WithISA Carteolol With ISA Celiprolol With MSA Betaxolol With MSA Carvedilol With MSA & ISA Labetalol
- 14. Β BLOCKERS With ISA Penbutolol Carteolol Celiprolol Both Pindolol Acebutolol Labetalol WithMSA Propranolol Metoprolol Betaxolol Carvedilol Without ISA & MSA Timolol, Sotalol, Nadolol Atenolol, Bisoprolol, Esmolol
- 15. PROPERTIES OF Β1SELECTIVITY Less broncho constriction Less interference with CHO metabolism less hypoglycemia preferred in diabetics Less chances of Raynaud's phenomenon Less deleterious effect on blood lipid profile Less impairment of exercise capacity Less effect on tremor
- 16. PROPERTIES OF ISA Lessbradycardia Less rebound effect on withdrawal Less deleterious effect on blood lipid profile Not effective in migraine prophylaxis Not suitable for secondary prophylaxis of MI
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- 18. ACTIONS…. On CVS Blood vessel Vasoconstrictionin prone individuals Direct Vasodilatation due to additional properties Precipitates Reynaud's disease •α1 blockade •β2 agonism •Ca ++ channel block •K+ channel opening •NO production
- 19. ACTIONS…. On CVS Antihypertensive action DecreasedCO Decreased TPR on long term administration Decreased renin release
- 20. BETABLOCKERS WITH VASODILATOR PROPERTY Alphablockade Labetalol Carvedilol Bucindolol Bevantolol Nipradilol Beta2 agonism Celiprolol Carteolol Bopindolol CCB action Betaxolol Bevantolol Carvedilol K+ Channel opening Tilisolol NO production Celiprolol Carteolol Bopindolol Nipradilol Nebivolol Anti oxidant Carvedilol
- 21. ACTIONS -CNS Anti anxiety Behaviourchanges Forgetfulness Night mares Increased dreaming Non-selective lipid soluble
- 22. ACTIONS -METABOLIC CHO metabolism Hypoglycemia Inhibitsmuscle glycogenolysis Hypoglycemic unawareness Lipid Increases VLDL(TG) levels Alters HDL/LDL ratio Less with β 1 selective agents
- 23. ACTIONS - EYE Decreasesecretion of aqueous Decrease IOT No effect on pupil size or accommodation Ciliary body
- 24. ACTIONS- BRONCHUS Increases airway resistance Lesswith beta 1 selective agents
- 25. SKELETAL MUSCLES o Decreaseexercise capacity By decreasing blood flow Inhibit glycogenolysis and lipolysis.
- 26. MISCELLANEOUS o Antagonise catecholamine induced Tremor Inhibitionof mast cell degranulation o Prevent platelet aggregation and promote fibrinolysis
- 27. Water soluble Lipid solubleByLiver By Kidney 100% 80 60 40 20 0 0 20 40 60 80 100% PROPRANOLOL TIMOLOL PINDOLOL BISOPROLOL ACEBUTOLOL ATENOLOL CARVEDILOL NADOLOL METOPROLOL SOTALOL LABETALOL CARTEOLOL PENBUTOLOL Pharmacokinetics
- 28. ADVERSE EFFECTS -CVS Bradycardia Exacerbation of angina Precipitation of CHF
- 29. ADVERSE EFFECTS… Increased airway resistance worsening of bronchial asthma
- 30. ADVERSE REACTIONS Impairment ofcarbohydrate tolerance Alteration of lipid profile Rebound hypertension on withdrawal Cold hands and feet, worsening of PVD
- 31. ADVERSE EFFECTS… Nightmares Decreased exercisecapacity Tiredness Lack of drive
- 32. DRUG INTERACTIONS PHARMACOKINETIC • Alsalts, Cholestyramine Decrease absorption • Enzyme inducers Decrease plasma conc. • Cimitidine, Hydralazine Increase BA • They impair clearance of lidocaine PHARMACODYNAMIC Digoxin CCB (Verapamil) CCB (DHP) NSAIDs Adrenaline & other α agonists
- 33. USES CARDIOVASCULAR Hypertension Angina Myocardial infarction Arrhythmia Cardiomyopathy CCF Dissecting aneurysmof aorta NON - CARDIOVASCULAR Thyrotoxicosis Pheochromocytoma Migraine prophylaxis Essential tremor Glaucoma Anxiety Portal hypertension Anti psychotic induced akathesia
- 34. HYPERTENSION Cardioselective beta blockers Rationale Decreasein HR,CO, myocardial contractility. Decrease renin release Decrease central sympathetic out flow
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- 36. ANGINA - RATIONALE DecreaseHR & contractility Decrease myocardial oxygen demand Antianginal action
- 37. MI o Prophylaxiso Treatment Anti anginal action Reduce infarct size Prevents arrhythmia Prevents reinfarction Prevents arrhythmia Metoprolol Esmolol Timolol
- 38. ARRYTHMIAS Propranolol Esmolol Acebutolol Sotalol Decreases AV conduction Inhibitsimpulses from atria to ventricle controls ventricular rate Mainly effective in Arrhythmias precipitated by catecholamines Sotalol K+ channel block class3 anti arrhythmic Esmolol ultra short acting supraventricular tachycardia
- 39. ARRHYTHMIA Control ventricular ratein atrial flutter and fibrillation. Suppress extrasystole and tachycardia especially mediated adrenergically .
- 40. HOCM ↓ contractility ↓ LVoutflow obstruction Improve cardiac output in exercise
- 41. CHF ONLY in compensatedCHF Antagonise sympathetic overactivity on myocardium Prevents myocyte apoptosis ↓ cardiac remodelling Retard progression of CHF Metoprolol Bisoprolol Carvedilol
- 42. DISSECTING AORTIC ANEURYSM ↓cardiac contractility, and aortic pulsation.
- 43. NON - CARDIACUSES o Pheochromocytoma Used after an α blocker To control tachycardia and arrhythmia Suppress cardiomyopathy due to excess catecholamines o Thyrotoxicosis Control sympathetic symptoms Inhibit peripheral conversion of T4 to T3 Preoperative use
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- 45. PORTAL HYPERTENSION To DecreasePortal Vein Pressure in Patients with Cirrhosis Decrease variceal bleeding Propranolol
- 46. GLAUCOMA Decrease aqueous humour secretion Attenuatingneuronal Ca and Na influx Protection to retinal neurons Inhibit ganglion cell death Timolol Carteolol Betaxolol Levobetaxolol Levobunolol Metipranolol
- 47. CNS Anxiety Essential tremor Akathisia inducedby antipsychotics Alcohol withdrawal
- 48. 3RD GENERATION AGENTS DrugMSA ISA Beta blockade Other properties Labetalol + + Non selective α1 blockade Carvedilol + Non selective α1 blockade,CCB Antioxidant Bucindolol + Non selective α1 blockade,β2,β3 agonism Increases HDL cholesterol Celiprolol + β1 selective β2 agonism NO release Nebivolol β1 selective •NO release •Inhibits platelet aggregation Bevantolol Nonselective α1 blockade CCB
- 49. CONTRAINDICATIONS Absolute 1. Severe Bradycardia 2.Pre-existing High Grade Heart Block 3. Overt Untreated Heart Failure 4. Cardiogenic Shock 5. Severe Bronchospasm 6. Severe Depression 7. Active Raynaud’s Phenomenon
- 50. CONTRAINDICATIONS Relative 1. Prinzmetals Angina 2.Concomitant Use Of :Verapamil/ Diltiazam/Digoxin 3. Mild Asthma 4. Insulin Requiring DM
- 51. OVERDOSAGE Manifestations extensionof pharmacological properties Hypotension Bradycardia Prolonged Conduction Times Widened QRS Complexes
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- 53. TREATMENT Atropine Initially Cardiac PacemakersRequired Large amt of Isoproterenol / Agonist Glucagon