module 7 beta blockers Flashcards
B1 selective
affects B1
dec. HR and BP
- Atenolol (tenormin)
- Bisoprolol (zebeta)
- Metoprolol (lopressor, Toprol)
- Nebivolol (bystolic)
Non selective BB
B1: heart -> dec. HR and BP
B2: lungs -> bronchoconstriction
- Carvedilol (coreg)
- Propranolol (inderal)
BB mechanism of action
Fits into receptor sites, blocking epi and norepi released from nerve endings
- heart: dec. CO -> dec. BP
- kidney: dec. activation of B1 -> dec. renin -> dec. angiotensin –> dec. Na and H2O retention -> dec. Blood volume -> dec. CO -> dec. BP
Benefits of beta blockade
dec. myocardial O2 demand
inc. ventricular filling (dec. HR)
antianginal
antiarrhythmic
selective BB adverse effects
hypoTN bradycardia heart block, heart failure fatigue dizzy
BB black box warning
abrupt cessation with CAD -> exacerbation of angina, MI, and ventricular arrhythmias
Mixed alpha-beta blockers
labetalol
carvedilol
labetolol mechanism of action and use
stronger alpha blockage than beta blockade (3:1)
- tx HTN and HTN urgency
carvedilol mechanism of action and use
nonselective beta blockade + a blockade
- tx: heart failure
nonselective BB adverse effects
hyper/hypoglycemia hypoTN bradycardia hyperkalemia hyperlipidemia
a1 blockers
doxazosin
prazosin
terazosin
labetalol (stronger A antagonist than B)
a1 blocker indications
HTN
BPH
a1 Blocker adverse effects
- first dose effect: lack of vasoconstrivtive mechanism -> postural hypoTN
- dizziness/lightheaded
- palpitations
- hypoTN
- fluid and Na retention
Contraindicated in: CV disease
a1 blocker (a1 adrenergic receptor antagonist) mechanism of action
causes peripheral arterial and venous vasodilation by blocking effects of catecholamines on alpha receptors of the peripheral vascular
central acting a2 receptor agonists
clonidine
methyldopa
guanfacine
central acting a2 agonist indication
HTN
central acting a2 agonists mechanism of action (methyldopa and clonidine)
reduces sympathetic outflow from vasopressor centers in brain stem and enhance PSNS activity -> dec. HR, CO, and total PVR
central acting a2 agonist adverse effects (methyldopa, clonidine)
sedation impaired concentration nightmares depression vertigo extrapyramidal s/s lactation in men ortho hypoTN dizzy dry mouth Na and H2O retention
methyldopa mechanism of action
converted to alpha-methydopamine and alpha-methylnorephinephrine in CNS
- stimulates central a2 -> dec. activity of vasomotor center
Renal blood flow maintain, good for renal disease
clonidine site of action
CNS non-adrenergic binding sites
- agonizes a2 receptors
clonidine route of admin
oral
transdermal: change every 7 days
clonidine indication
HTN
induce sleep
minimize s/s of withdrawal from opiates or benzos
clonidine contraindication
tricyclic antidepressant use
- inhibit norepi reuptake and block the effects of clonidine
