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Beta Blocker

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Beta Blocker, Beta-Blocker, Beta Adrenergic Antagonist, Beta Adrenoceptor Blocking Drug, Atenolol, Timolol, Nadolol, Acebutolol, Sectral, Bisoprolol, Zebeta, Betaxolol, Kerlone, Corgard, Penbutalol, Levatol, Oxprenolol, Carteolol, Tenormin, Nebivolol, Bystolic, Pindolol, Visken

  1. Sir James Black won 1988 Nobel Prize for Propranolol
  2. Synthesized Propranolol first in the 1960's
  3. Revolutionized cardiovascular medicine
  • Indications
  1. Hypertension
  2. Atrial Fibrillation Rate Control
  3. Coronary Artery Disease without prior Myocardial Infarction
    1. Consider to reduce Anginal symptoms and improve Exercise tolerance
  4. Myocardial Infarction without Congestive Heart Failure
    1. Continue for at least 2-3 years after Myocardial Infarction
  5. Stable Congestive Heart Failure (Carvedilol, Metoprolol, Bisoprolol)
    1. Continue Beta Blocker indefinately
  6. Arrhythmia refractory to other modality
    1. Recurrent Ventricular Tachycardia
    2. Recurrent Ventricular Fibrillation
  7. Migraine Prophylaxis
  8. Endocrinopathy
    1. Thyroid Storm
    2. Pheochromocytoma
      1. Never use Beta Blocker without Alpha Adrenergic Receptor Antagonist in Pheochromocytoma
  9. Open Angle Glaucoma
    1. See Intraocular Beta Blocker
  • Contraindications
  1. Reactive Airway Disease and Obstructive Lung Disease (Asthma, COPD)
    1. Cardioselective Beta Blockers (e.g. Metoprolol) are not contraindicated
    2. Avoid non-selective Beta Blockers (Carvedilol, Propranolol)
    3. See Bronchospasm under adverse effects below
  2. Acute Congestive Heart Failure exascerbation (decompensated CHF)
  3. Concurrent Calcium Channel Blocker use
    1. Relative contraindication (risk of AV Block, Bradycardia)
  • Precautions
  1. Abrupt discontinuation is associated with exacerbation of Angina and risk of MI (FDA black box warning)
  2. Taper over one to two weeks
  1. Beta Adrenergic Receptor Antagonist
  2. Inhibits effects of circulating Catecholamines
  3. Blocks Beta Adrenergic Receptors
    1. Beta-1 Adrenergic Receptors (Selective Beta Blockers primarily inhibit B1)
      1. Cardiac muscle (primarily contraction)
      2. Allow Calcium entry into cells (cAMP mediated)
      3. Inotropic and chronotropic effects
    2. Beta-2 Adrenergic Receptors
      1. Smooth muscle and Bronchioles
    3. Beta-3 Adrenergic Receptors
      1. Lipolysis
  1. General Cardiac Effects
    1. Negative Inotrope
      1. Reduces Myocardial Contractility
    2. Negative Chronotrope
      1. Reduces Heart Rate
    3. Reduces Blood Pressure
    4. Reduces Myocardial Oxygen Demand
  2. Antiarrhythmic effects
    1. Seen with non-selective Beta Blockers (Propranolol)
    2. Controls Catecholamine stimulated Arrhythmias
      1. Recurrent Ventricular Tachycardia
      2. Recurrent Ventricular Fibrillation
    3. Controls Myocardial Ischemia related Arrhythmias
    4. Reduces AV Nodal Conduction
      1. Slows ventricular response
        1. Atrial Fibrillation
        2. Atrial Flutter
        3. Paroxysmal Supraventricular Tachycardia
      2. Quinidine-like effect on Action Potential
        1. Seen with Propranolol
  3. Myocardial protection
    1. Reduces Myocardial Infarction size
    2. Prevents re-infarction after Thrombolytic
  • Mechanism
  • Non-Selective effects (non-cardiovascular effects)
  1. Beta 2 Adrenergic Receptor blockade
    1. Results in bronchoconstriction
      1. Beta 2 Adrenergic Receptors affect Bronchiole and smooth muscles
    2. Non-Selective Beta Blockers (e.g. Propranolol)
    3. Selective Beta Blockers lose selectivity at high dose and in Overdose
      1. High dose Metoprolol (over 200 mg/day)
      2. High dose Esmolol (over 300 ug/kg/min)
  2. Beta 3 Adrenergic Receptor blockade
    1. Lipolysis inhibited
  • Adverse Effects
  1. SA and AV nodal blockade
    1. Avoid in over age 75 unless secondary indication
    2. Do not use with Calcium Channel Blockers
  2. Hypotension or Orthostasis
  3. Congestive Heart Failure
    1. Treat with vasodilators and Diuretics with inotropes
  4. Bradycardia
    1. Treat with Atropine, Transcutaneous pacing, Dopamine
  5. Bronchospasm
    1. Treat with Sympathomimetics and Aminophylline
    2. Unlikely to occur in cardioselective Beta Blockers at standard doses
      1. Study looked at Atenolol, Metoprolol, Bisoprolol
      2. First dose may lower FEV1 (responds to Albuterol)
      3. Continuous use does not impair lung function
      4. Salpeter (2002) Ann Intern Med 137:715-25 [PubMed]
  6. Major Depression exacerbation
  7. Fatigue
  • Drug Interactions
  1. Decreased Heart Rate and AV Conduction (cummulative effects of multiple agents acting at AV Node)
    1. Amiodarone
    2. Diltiazem
    3. Verapamil
    4. Propafenone (Rythmol)
    5. Sotalol (Betapace)
  2. Beta Blockers potentiate effects of other agents
    1. Digoxin
    2. Lidocaine
  • Preparations
  • Cardioselective (Beta-1 Selective Adrenergic Blockade)
  1. Atenolol (Tenormin)
    1. Despite daily dosing, duration of activity is not a a full 24 hours
      1. Consider dividing dosing into twice daily (e.g. 50 mg twice daily)
    2. Not as effective as other Beta Blockers in cardiovascular disease prevention (especially with Hypertension present)
      1. Consider Metoprolol, Bisoprolol, Carvedilol or Nadolol instead
      2. Carlberg (2004) Lancet 364:1684-9 [PubMed]
    3. Dosing Adults
      1. Start: 25-50 mg orally daily
      2. Target: 50-100 mg orally daily (may divide dose twice daily)
      3. Maximum dose: 100 mg (50 mg if GFR <35 ml/min, 25 mg if GFR <15 ml/min)
  2. Metoprolol (Lopressor, Toprol XL)
    1. See Metoprolol
    2. Preferred Beta Blocker for Hypertension, Myocardial Infarction, Atrial Fibrillation Rate Control
    3. Metoprolol Succinate (Toprol XL) is preferred over Metoprolol Tartrate (Lopressor)
  3. Bisoprolol (Zebeta)
    1. Most cardioselective of Beta Blockers
    2. Start: 2.5 to 5 mg orally daily
    3. Maximum: 20 mg/day
  4. Betaxolol (Kerlone)
    1. Start: 5 mg orally daily
    2. Maximum: 20 mg/day
  5. Acebutolol (Sectral)
    1. Intrinsic Sympathomimetic activity (partial beta agonist)
    2. Start: 400 mg orally daily or divided 200 mg orally twice daily
      1. Better efficacy when divided twice daily
    3. Target: 400 to 800 mg/day
    4. Maximum: 1200 mg/day
  • Preparations
  • Nonselective (Beta-1 and Beta-2 Adrenergic Blockade)
  1. Timolol (Blocadren)
    1. Dose: 10 mg orally twice daily (maximum 60 mg/day)
  2. Nadolol (Corgard)
    1. Dose: 40 mg orally daily (maximum 320 mg/day)
    2. Decrease dose with Renal Insufficiency
  3. Propranolol (Inderal)
    1. Used for Essential Tremor, symptomatic Hyperthyroidism, Migraine Prophylaxis, symptomatic Palpitations
  4. Timolol
    1. See Intraocular Beta Blocker
    2. Typically used topically for Open Angle Glaucoma
    3. Longer half life than Propranolol
  5. Sotalol
    1. Primarily used as Antiarrhythmic
  6. Penbutalol (Levatol)
    1. Start: 20 mg orally daily
    2. Target: 20-40 mg orally daily
    3. Maximum: 80 mg/day
  7. Oxprenolol
    1. Dose: 80-160 mg orally divided twice to three times daily
    2. Maximum: 320 mg/day
  8. Carteolol (Cartrol)
    1. Start: 2.5 mg orally daily
    2. Target: 2.5 to 5 mg orally daily
    3. Maximum: 10 mg/day
    4. GFR <60: decrease dose to every 48 hours
  9. Pindolol (Visken)
    1. Intrinsic Sympathomimetic activity (partial beta agonist)
    2. Start: 5 mg orally twice daily
    3. Target: 5 to 15 mg orally twice daily
    4. Maximum: 60 mg/day
  • Preparations
  • Combined Beta Blocker and Vasodilator
  1. Combined Alpha-1, Beta-1 and Beta-2 Adrenergic Blockade
    1. Labetalol
      1. Used in Hypertension in Pregnancy, Resistant Hypertension, CVA Blood Pressure Control
    2. Carvedilol (Coreg)
      1. Third generation Beta Blocker with vasodilatory properties (alpha blocker)
      2. Used in Congestive Heart Failure
  2. Combined Beta-1 and NItric Oxide (Beta-3 Agonist)
    1. Nebivolol (Bystolic)
      1. Third generation Beta Blocker with vasodilatory properties (nitric oxide release)
      2. Dosing
        1. Start: 5 mg orally (2.5 mg in hepatic Impairment or GFR <30 ml/min)
        2. Maximum: 40 mg/day
  • Preparations
  • Parenteral Beta Blockers
  • References
  1. (2012) Presc Lett 19(12): 67-8
  2. Yen (2015) Crit Dec Emerg Med 29(10): 18-23