alpha and beta blockers Flashcards
phenoxybenzamine
- alpha 1 antagonist (some alpha 2)
- rx pheochromocytoma
phentolamine
- nonselective alpha blockade
- acute hypertensive emergency
consider beta-blockade if:
- known CAD (hx MI, angina, + stress, PVD)
- two of: age >50, HTN, current smoker, HLD, DM
should not receive periop beta blockade
- sensitivity to beta-blockers
- 2nd, 3rd degree HB
- acute CHF
- acute bronchospasm
- SBP<60
- acute hemodynamically unstalbe patient
- be careful in pts with asthma/COPD
periop beta blockade choices
- atenolol, bisoprolol, metoprolol–all long acting b-1 blockers, prevent death after MI
- keep HR<80
propranolol
- negative inotrope and chronotrope
- decreases CO, HR, esp in exercise
- dec myocardial O2 consumption
indication for propranolol
- HTN: direct cardiac effects and suppresses RAA system
- angina
- dysrhythmias
propranolol: PK
- absorbed by GI tract, 1st past in liver
- elimination reduced when liver blow flow low, or when hepatic metabolism is retarded by cimetidine
- extensively protein bound
- older pts experience inc bioavailability
propranolol: contraindications
- Heart failure, AV block
- severe asthma/COPD–relative CI–propranolol blocks b2 receptors–constriction of bronchial smooth muscle and worsening asthma
propranolol: side effects-airway
-increases airway resistance, exaggerated in setting of COPD
propranolol: side effects-carbohydrate metabolism
- blocks effects of catecholamines to increase blood sugar
- has hypoglycemic effect, potientiates effect of insulin
propranolol: side effects-potassium
-inhibits intracellular K+ uptake, leading to hyperkalemia
propranolol: side effects-placenta
-leads to fetal bradycardia, hypotension, hypoglycemia
selective beta blockers
- atenolol
- metoprolol
- esmolol
labetalol
-labetalol–alpha1 antagonist, nonselective beta1/beta 2 antagonist
