This document discusses beta blockers, including their classification, mechanisms of action, uses, and side effects. It notes that beta blockers work by blocking beta-1 and beta-2 adrenergic receptors. They are commonly used to treat hypertension, angina, arrhythmias, and myocardial infarction. Specific drugs like metoprolol, atenolol and carvedilol are mentioned as preferred treatment options depending on the condition. Potential adverse reactions include worsening heart failure, bradycardia, bronchospasm, and metabolic effects.

1. Dr Venkatesh Karthikeyan
Intern
VMCH & RI
Email : 4852012@gmail.com
13/09/2019

2. ANS
 Sympathetic (Adrenergic)
 Parasympathetic (Cholinergic)

3. Cholinergic
 Muscarinic (M1, M2, M3)
 Nicotinic (Nm, Nn)

4. Adrenergic
 Alpha (1 and 2)
 Beta (1,2,3)

5. Beta 1 receptors
 In heart, JG cells of kidney
 Selective agonist - Dobutamine
 Selective antagonist – Metoprolol, Atenolol

6. Beta 2 receptors
 In Bronchi, blood vessels, uterus, liver, GIT, GUT, Eye
 Selective agonist – Salbutamol, terbutalin
 Selective antagonist – Alpha methyl propanolol

7. Beta 3 receptors
 In adipose tissue

8. Classification
 First generation (Older, non selective)
 Second generation (Beta 1 selective)
 Third generation (with additional alpha blocking
and/or vasodilator property)

9. First generation
Propanalol
Timolol
Sotalol
Pindolol

10. Second generation
Metaprolol
Atenolol
Acebutolol
Bisoprolol
Esmolol

11. Third generation
Labetolol
Carvedilol
Celiprolol
Nebivolol
Betaxolol

12. Pharmacological actions
 CVS
 Respiratory tract
 CNS
 Local Anaesthetic
 Metabolic
 Skeletal muscle
 Eye
 Uterus

13. CVS - Heart
 Decreases heart rate
 Decreases force of contraction
 Decreases cardiac output
 Effects are prominent under sympathetic overactivity

14.  CHF may be aggravated
 In angina patients, improvement of oxygen
supply/demand status, exercise tolerance is increased.

15. CVS – Blood vessels
 On prolonged administration, propanolol causes
gradual fall in BP in hypertensive patients.

16. Respiratory tract
 Increases bronchial resistance
 Asthma may be precipitated

17. CNS
 Subtle behavioural changes
 Forgetfulness
 Increased dreaming
 Nightmares
 Suppresses anxiety

18. Local anaesthesia
 Proponolol – Potent local anaesthetic
 Causes irritation at injected site

19. Metabolic
 Blocks adrenergically induced lipolysis
 Causes increase in plasma free fatty acid level
 Plasma triglyceride level increases
 LDL/HDL ratio is increased

20. Skeletal muscle
 Inhibits adrenergically provoked tremor
 Reduce exercise capacity

21. Eye
 Reduces secretion of aqueous humor
 IOT is lowered

22. Uterus
 Relaxation of uterus in response to Beta 2 agonists is
blocked

23. Uses
 Hypertension
 Angina pectoris
 Cardiac arrhythmias
 Myocardial infarction
 Congestive heart failure
 Dissecting aortic aneurysm

24. Uses
 Pheochromocytoma
 Thyrotoxicosis
 Migraine
 Anxiety
 Essential tremor
 Glaucoma
 HOCM

25. Hypertension
 First line
 Good patient acceptability
 Cardioprotective

26. Angina Pectoris
 Decreases frequency of attacks
 Increases exercise tolerance
 Not suitable in vasospastic angina

27. Cardiac arrythymias
 Supresses extrasystoles and tachycardias, especially
those mediated adrenergically – during anaesthesia/
digitalis induced
 Controls ventricular rate in AF and atrial flutter
 Esmolol - PSVT

28. Myocardial infarction
 Secondary prophylaxis of MI
 Myocardial salvage during evolution of MI

29. Secondary prophylaxis of MI
 Prevents reinfarction
 Prevents sudden ventricular fibrillation at subsequent
attack of MI

30. Myocardial salvage during MI
 Limit infarction size by reducing O2 consumption
 Prevents arrhythmias
 Can be administered only those who are not in
shock/cardiac failure/ bradycardia

31. Congestive heart failure
 Useful in selected patients with DCM
 Prevents deleterious effects of sympathetic overactivity
invoked reflexly by heart failure

32. Dissecting aortic aneurysm
 Reduces cardiac contractile force
 Decreases aortic pulsation

33. Pheochromocytoma
 Used to control tachycardia and arrhythmias
 Never administer unless an alpha blocker is given
– otherwise dangerous rise in BP can occur.

34. Thyrotoxicosis
 Rapidly controls sympathetic symptoms
 Inhibits peripheral conversion of T4 to T3

35. Migraine
 Most effective for chronic prophylaxis

36. Anxiety
 Blocks peripheral manifestations of anxiety

37. Essential tremor
 Does not benefit parkinsonian tremor (resting)

38. Hypertrophic obstructive
cardiomyopathy
 Beta blockers reduce left ventricular outflow
obstruction
 Improves cardiac output in these patients during
exercise

39. Glaucoma
 Timolol
 Betaxolol
 Levobunolol

40.  Advantages over miotics
 No change in pupil size
 No diminution of vision in dim light/cataract patients
 Does not induced myopia
 No persistant spasm of iris and ciliary muscles/ No
headache and brow pain
 No IOT fluctuation

41. Perioperative Cardiovascular death
 Increased sympathetic response
 Imbalance in oxygen supply and demand
 Plaque rupture
 Thrombosis
 Occlusion

42. Cardioprotective effects in
perioperative patients
 Decreased oxygen demand
 Increased systolic perfusion time
 Suppresses arrhythmia
 Stabilizes plaque
 Anti inflammatory response
 Inhibits apoptosis

43. In Non Cardiac surgery
 Beta blockers should be titrated against
hemodynamics over a period of days before surgery
 Protective against MI and have preventive/therapeutic
benefits in arrhythmias
 Decreases incidence of mortality due to cardiac cause

44. In Cardiac surgery
 Prevent and treat perioperative arrhythmia in CABG
and valvular disease
 Beneficial in MI (age<75 years, EF >30%)
 Mortality benefits of beta blockers have been
conclusively proven in large studies

45. Individual drugs
 Sotalol – Class III antiarrhythmic activity
 Timolol – glaucoma
 Pindolol – Antihypertensive used in patients who
develop bradycardia with propanolol
 Metoprolol – prefered in diabetics

46.  Atenolol – MC used in hypertension and angina / once
daily dose/ does not derange lipid profile
 Acebutolol - once daily dose
 Bisoprolol – once daily dose in angina/CHF/SHT

47.  Esmolol
 Ultrashort acting (T1/2 – 10 mins)
 Terminates SVT
 Useful in AF/flutter
 Useful in arrythmia during anaesthesia
 Reduces HR and BP during and after cardiac surgery
 In early treatment of MI

48.  Celiprolol – safe in asthmatics
 Nebivolol – delays atherosclerosis
 Labetolol – alpha + beta blocker / potent hypotensive
(20-40 mg IV every 10 mins in hypertensive
emergencies)

49.  Carvedilol
 Alpha 1 + Beta 1 + Beta 2 blocker
 Antioxidant property
 Cardioprotective

50. Interactions
 Delays recovery from hypoglycemia due to
antidiabetics
 Warning signs of hypoglycemia masked
 Retards lignocaine metabolism
 Increases bioavailability of chlorpromazine

51. ADR
 Can precipitate CHF/edema
 Bradycardia (sick sinus patients are more prone)
 Contraindicated in asthmatics
 Exacerbates vasospastic angina
 Plasma lipid profile altered
 Enhances risk of of CAD

52.  Sudden withdrawal of propanolol – rebound
hypertension / worsening of angina / death
 Contraindicated in heart block
 Tiredness and decreased exercise capacity
 Worsening of peripheral vascular disease
 Sexual distress
 GI upset

53. Thank you 