Quick summary of Beta Blockers
β1-receptors: affects heart rate, conduction and contractility
β2-receptors: cause smooth muscle contraction, bronchospasm in predisposed
Classified into three generations
- first generation
- (Propranolol, Sotalol, Timolol, Nadolol)
- nonselective: block β1 and β2 receptors.
- 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
- 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.