β-blockers Flashcards
What are the effects of β-blockers on Angina pectoris?
↓ heart rate and contractility, resulting in ↓ O2 consumption
What are the effects of β-blockers on MI?
↓ mortality (metoprolol, carvedilol, and bisoprolol)
What are the effects of β-blockers on SVT (metoprolol, esmolol)?
↓ AV conduction velocity (class II antiarrhythmic)
What are the effects of β-blockers on Hypertension?
↓ cardiac output, ↓ renin secretion (due to β1-receptor blockade on JGA cells)
What are the effects of β-blockers on CHF?
Slow progression of chronic failure
What are the effects of β-blockers on Glaucoma (timolol)?
↓ secretion of aqueous humor
What are the toxicities of β-blockers?
Impotence, CV adverse effects (bradycardia, AV block, CHF), CNS adverse effects (seizures, sedation, sleep alterations), dyslipidemia (metoprolol), and asthmatics/COPDers (may cause exacerbation)
Why should β-blockers be avoided in cocaine users?
Risk of unopposed α-adrenergic receptor agonist activity
Why are β-blockers not contraindicated in diabetics?
Despite theoretical concern of masking hypoglycemia in diabetics, benefits likely outweigh risks
Which β-blockers are β1-selective antagonists (β1 > β2)?
Acebutolol (partial agonist), Atenolol, Betaxolol, Esmolol, metoprolol (Selective antagonists mostly go from A to M (β1 with 1st half of alphabet))
Which β-blockers are nonselective antagonists (β1 = β2)?
Nadolol, Pindolol (partial agonist), Propranolol, Timolol (Nonselective antagonists mostly go from N to Z (β2 with 2nd half of alphabet))
Which β-blockers are nonselective α- and β-antagonists?
Carvedilol and labetalol (not “-olol”)
What does Nebivolol do?
Combines cardiac-selective β1-adrenergic blockade with stimulation of β3 receptors, which activate NO synthase in the vasculature
