Beta-Blockers Flashcards
MOA of BB w/ no ISA
decrease HR and contractility–> Decrease CO
inhibit renin release (EXCEPT Pindolol)
Decrease central sympathetic outflow (except for those w/ low lipid solubility)
Decrease release of peripheral NE by inhibiting presynaptic beta adrenergic receptors
Pindolol
does not inhibit decrease renin release
High ISA, some MSA, no cardioselectivity, lipid soluble
Utility of BB w/ no ISA
Especially useful in pts w/ high renin level HTN
Effects of BBs w/ no ISA
w/ chronic use…
decrease CO and peripheral resistance and arterial pressure
Clinical uses of 1st and 2nd generation B-blockers in HTN
effective therapy for all grades of HTN
Clinical uses of 1st and 2nd generation B-blockers in HTN…
More effective in…
High renin HTN
young and caucasian
Clinical uses of 1st and 2nd generation B-blockers in HTN:
Less effective in…
Low renin HTN
elderly and AA
BBs and diuretics
BBs do not cause H20 and salt retention
–so can be administered w/out diuretic
But has additive antihypertensive effect when administered w/ diuretic
Highly preferred in hypertensive pts w/…
MI ischemic heart disease HF hyperthyroidism migraines
CHF
3rd generation BBs
carvedilol
metaprolol-XL
bisoprolol
MI
useful in preventing 2nd MI
perhaps b/c of bradycardia?
Other indications
Sinus and AV arrhythmias
open angle glaucoma
anxiety
Propranolol uses
Non-selective BB that produces resting bradycardia and decrease HR during exercise –> hypotension
membrane stabilizing activity: antiarrhythmic
produces bronchospasm; contraindicated in asthmatics
slow withdrawal of drug to prevent reflex tachycardia
Metoprolol and Atenolol
50-100-fold more selective in blocking β1-adrenergic receptors
“Cardioselective agents”
Bisoprolol
Long-acting drug (take once a day
significantly decreases all case mortality
glaucoma eyedrops
PIndolol and acebutolol
Non-selective drugs with partial agonist activity.
Decrease CO and HR less than other drugs.
Esmolol
ARRHYTHMIAS!!!
Selective drug w/ VERY short half-life
Given IV for management of tachycardia, arrhythmias during surgery and postoperative tachycardia caused by halothane anesthetic
Timolol
non-selective drug
eye-drops for Rx of chronic open angle glaucoma
Side effects
Cold extremities
Bradycardia
Bronchospasm (avoid ALL drugs w/ asthma; permitted w/ COPD)
CNS side effects
Metabolic
Drug withdrawal syndrome
fatigue, decreased exercise tolerance, impotence
Cold extremities side effect
- -Unopposed α adrenergic action constricts BV in the skin and limits blood flow causing cold extremities.
- -Prolonged use worsens peripheral arterial insufficiency; Raynaud’s phenomenon.
Bradycardia side effect
Decreased AV nodal conduction; contraindicated with verapamil
and diltiazem
Metabolic side effects
- Block glycogenolysis and delay recovery from hypoglycemia in type 1 diabetics (seen with non-selective drugs but less frequently with ß1-selective agents).
- Block HSL in adipocytes and increase LDL and reduce HDL and increase triglycerides.
Drug withdrawal syndrome
Prolonged drug use upregulates β-receptors in the heart.
Abrupt withdrawal causes tachycardia; withdraw slowly!!!!
3rd Generations:
Labetalol
non-selective beta + a1 antagonist
given IV for HTN emergencies
3rd Generations:
Carvedilol
non-selective β + α1-receptor antagonist
By blocking α1-AR, CO maintained with increased fall in peripheral resistance.
- Antioxidant; binds and scavenges ROS
- Protects membranes from lipid peroxidation. Prevents LDL oxidation and decreases LDL uptake into coronary blood vessels.
- Primarily used for CHF & HTN; decreased mortality and morbidity in pts w/ mild to moderate CHF
- PO; extensively protein bound; hepatic (2D6) metabolism
3rd Generations;
Celiprolol
Cardio-selective + beta2 agonism
Directly vasodilates BV due to partial ß2- agonist activity.
Used for treatment of HTN and angina.
3rd Generations
Nebivolol
drugs w/ NO mediated vasodilation
Highly β1 selective; devoid of ISA, membrane stabilizing activities, and α1 blocking activities.
- Has antioxidant activity/neutral to favorable effects on both carb and lipid metabolism.
- decreased BP by decreasing HR and peripheral vascular resistance.
- Significantly increases stroke volume, maintains CO and systemic blood flow.
- Drug of choice for HTN with metabolic syndrome!!!
Propanolol
MSA, lipid soluble
Metoprolol
some MSA, cardioselective, lipid soluble
Atenolol
cardioselective, NOT lipid soluble
Timolol
some ISA, lipid soluble
