Beta Blockers (Stable Angina CAD) Flashcards
MOA Beta Blocker Class
Lower myocardial o2 demand -reduce ischemic time -↓ HR -↓BP and workload -↓contractility slower rates improve venous perfusion and ventricular filling -Slow PR interval -Slow ventricular rate -Reduces Renin output -Decreased RAAS activity
all BB have dose related b1/b2 activity
Indications for Beta Blockers
Preferred when tolerated
Best data for reducing CV events!
Good for open angle glaucoma (↑outflow and drainage)
Perioperatively in high risk pts undergoing non cardiac surgery
Metabolism of Beta Blockers
Short half life*
Hepatic metabolism* (hepatic failure might not tolerate BB at therapeutic doses)
Rapidly absorbed
Large volume of distribution
Contraindications of BB
relatively CI in COPD
Renal insufficiency* increased toxic effect
Caution in pts with pulmonary dz
Pts with pulm dz can tolerate in low doses
Caution in DM-masks hypoglycemia
BB outcome benefits
- ↓mortality in htn pts with recent MI
- ↑survival in htn pts after stroke
- ↑exercise tolerance!! (initially difficult) 25-50% tolerate doses
BB DI
DI BB with verapamil or diltiazem
Nonselective: carvedilol (post mi, LV dysfunction, heart failure); labetalol, nadolol, sotalol, timalol
Selective: metoprolol (heart failure or post MI), biosprolol (heart failure or LV dysfunction), atenolol, esmolol, nebivolol
ISA and partial agonism are not clinically important
*fyi bb can mask thyroid strome or thyrotoxicosis (vtach)
Considerations of BB
TAPER!!! To prevent rebound
-takes 2-4 weeks for full effect but will see bp decrease in 24 hrs
B1 selective (can still block B2 at high doses)
B2: bronchioles and peripheral vascular tissue for vasodilation; unopposed alpha constriction
Monitor: HR, BP, EKG, Physical function
Metoprolol MOA
Selective B1 Blocker ↓inotropy ↓chonotropy ↓cardiac work ↓MV02 (reduced selectivity in higher doses)
Metoprolol indications
Asthma
COPD
LIVER dz (little protein binding)
Metroprolol considerations
Adjusted to bp, hr, ekg (minimum sbp 90, minimum hr 50)
- most frequently used BB
- *evidence for reducing CV events in pts with HTN, HF, LVF, CAD
Bisprolol MOA
Selective Beta Blocker ↓inotropy ↓chonotropy ↓cardiac work ↓MV02
Bisprolol indications and meteabolism precautions
I: HF pts with HTN
M: Adjust in pts with renal dysfunction bc long half life
50% of dose is excreted unchanged
Bisprolol SE and
Considerations
Can precipitate decompensated HF if used in UNSTABLE pts with stage III/IV HF
Evidence based BB in HF pts with HTN
Carvedilol MOA
1.nonselective BB
2. alpha 1 blocker***
(= less rebound tachycardia)
↓renin output
↓inotropy
↓chonotropy
↓cardiac work
↓MV02
Carvedilol indcation
Metabolism
I:HF
M: Extensive hepatic metabolism: CYP2D6
Adjusted to bp, hr, ekg (minimum sbp 90, minimum hr 50
SE of Carvedilol
Less rebound tachycardia!! Following hypotension
Considerations of Carvedilol
*Evidence in HF, reducing MI
might reduce smooth muscle infiltration in vascular remodeling, limit free radicals, reduce lipid peroxidation
Propranolol MOA
Nonselective Lipophilic ↓inotropy ↓chonotropy ↓cardiac work ↓MV02
Propranolol indications
h/a prophylaxis with CAD
-Short acting*
1-2 hr onset and lasts 6-12 hrs
-Long Acting* slower onset and lasts 24-27 hrs and even longer in liver dz*
Propranolol metabolism
high 1st pass metabolism (CYP2D6/1A2)
highly protein bound (90%)
Adjusted to bp, hr, ekg (minimum sbp 90, minimum hr 50)
Nadolol MOA
Nonselective ↓inotropy ↓chonotropy ↓cardiac work ↓MV02
Nadolol Metabolism
Non-metabolized: 45 hr duration in pts with renal failure—dose adjust!
Nadolol SE
Can cause bronchoconstriction in large dose
↓hepatic blood flow with beta2 blockade
Nadolol Considerations
OK in Liver Dz
Adjusted to bp, hr, ekg (minimum sbp 90, minimum hr 50)
Atenolol MOA
Selective B1 Blocker ↓BP ↓HR ↓inotropy ↓chonotropy ↓cardiac work ↓MV02
Atenolol Indications
Asthma
COPD
Liver dz (little protein binding and limited hepatic met)
Atenolol considerations
↓BP
↓HR
but no CV outcomes in HTN with CAD or HF
little hepatic metab.
Labetalol MOA
1.Nonselective BB (R isomer)
2.Selective alpha 1 blockade (S)
↓ renin output
Labetalol Metabolism
Alpha:beta is 1:3 oral vs 1:7 IV
Adjusted to bp, hr, ekg (minimum sbp 90, minimum hr 50)
Labetalol SE
less rebound tachycardia in alpha1!
Esmolol indications
Perioperative use in HTN, myocardial Ischemia, thyrotoxicosis, VT
Esmolol Metabolism
ultra short acting!!
For perioperative use***
2-10 min onset, 10-30 min duration
Has ester linkage for rapid hydrolysis by RBCs
Nebivolol MOA
Most selective B1 antagonist with endothelium derived nitric oxide dependent vasodilation
↓HR, BP SVR
Nebivolol metabolism
12%bioavailable
*protein binding 98%
met by CYP2D6
half life 10-12 hrs nml or 32 hrs in poor met
Nebivodol contraindications
reduce dose in child pugh class B pts
Reduce dose in CrCl
Nebivodol SE
no hyperglycemic or lipid issues like other BB!!
Nebivodol Contraindications
No role in angina
Reduces hospitalizations of elderly pts with HF