Beta Blocker Classification

Quick summary of Beta Blockers

beta blockers

β1-receptors: affects heart rate, conduction and contractility

β2-receptors: cause smooth muscle contraction, bronchospasm in predisposed

Classified into three generations

  1. first generation
    • (Propranolol, Sotalol, Timolol, Nadolol)
    • nonselective:  block β1 and β2 receptors.
  2. second-generation agents
    • (Atenolol, Bisoprolol, Celiprolol, Metoprolol)
    • cardioselective agents
    • block β1-receptors in low doses, block β2-receptors in higher doses.
    • more suitable in chronic lung disease or insulin-requiring diabetes mellitus
    • Bisoprolol most selective
  3. third generation agents
    • either selective (Nebivolol) or nonselective (Carvidolol and Labetolol)
    • vasodilatory properties mediated either by nitric oxide release (Nebivolol or Carvedilol) or by alpha-adrenergic blockade (Labetolol and Carvedilol)

B blockers with ISA

  • third vasodilatory mechanism (Pindolol, Acebutolol) acts via β2-intrinsic sympathomimetic activity (ISA)
  • stimulate as well as to block adrenergic receptors
  • cause less bradycardia than the other beta-blockers and may cause less coldness of the extremities.


Khaled Albouaini, Mohaned Egred. ‘Beta-Blockers Use In Patients With Chronic Obstructive Pulmonary Disease And Concomitant Cardiovascular Conditions’. International Journal of Chronic Obstructive Pulmonary Disease 2.4 (2007): 535. Web. 23 Oct. 2015.

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