Beta Blockers HTN

Question 1

Types of Beta receptors in SA Node and affect

Answer 1

B1&B2; accelerates node

Question 2

Types of Beta receptors in Ectopic Pacemakers and affect

Answer 2

B1 and B2; accelerates ectopic pacemakers

Question 3

Types of Beta receptors in contractile myocytes and affect

Answer 3

B1&B2; increases contractility

Question 4

Types of Beta receptors in skeletal muscle and affect

Answer 4

B2 and relaxes skeletal vasculature

Question 5

Beta 1 specific drugs

Answer 5

A=>N drugs

Acebutolol, Alprenolol, Atenolol, Betaxolol, Celiprolol, Nebivolol

Question 6

Nonspecific beta blockers

Answer 6

O=>Z drugs

Propranolol, Penbutolol, Pindolol, Timolol

Question 7

B2 specific drugs

Answer 7

Butoxamine - experimental drug only

Question 8

Beta blockers with high lipid solubility and consequence of it

Answer 8

Penbutolol and Propanolol; can have CNS affects such as bad dreams

Question 9

Beta blocker with shortest half life

Answer 9

Esmolol

Question 10

Drugs with membrane stabilizing activity

Answer 10

Propanolol, acebutolol, carvedilol - antiarrythmics through class 1 mechanism of blocking Na channels and affecting phase 0

Question 11

Intrisnic sympathomimetic activity

Answer 11

Drugs that can induce partial receptor activity in the absence of catecholamines, can be used to prevent profound bradycardia or negative isotropy - propranolol, pindolol, acebutolol

Question 12

Antagonists with extended actions

Answer 12

Carteolol - NO production and B2 receptor agonism

Carvedilol - alpha 1 receptor antagonism, Ca2+ entry blockage, antioxidant activity

Nebivolol - NO production

Labetalol - alpha 1 receptor antagonism

Betaxolol - Ca2+ blockade

Question 13

How beta blockers can change BP

Answer 13

don’t reduce BP in normotensive, only hypertensive patients

Variable affect on renin release from JGA

Presynaptic autoreceptors enhance NE release

Long term administration leads to fall in PVR

CNS affect is variable depending on lipid solubility - drugs that poorly penetrate BBB are still effective antihypertensives

Question 14

Adverse CV Effects

Answer 14

CHF in at risk patients (compensated HF, acute MI, cardiomegaly)

Bradycardia; arrythmic brady in pts with AV defects

Decreased peripheral blood flow - cold extremities

Abrupt discontinuation can exacerbate angina and increase risk of sudden death

Question 15

Pulmonary side effects

Answer 15

Blockade of bronchial smooth muscle by Beta2 receptors - promoting bronchodilation in patients with bronchospastic disease

Life threatening increase in airway resistance

Avoid non-specific beta blockers in patients with lung conditions but even B1 specific are not absolutely receptor specific so may need to avoid as well

Question 16

CNS Side effects

Answer 16

Lipophilic drugs can cause depression, mental disorders, fatigue, and vivid dreams

Question 17

Effects on glucose

Answer 17

Block lipolysis - increased tricglycerides and decrease plasma HDLs

Can cause hypoglycemia and masks the tachycardia typical of uncontrolled diabetes so avoid in diabetic patients