CHAPTER 7: ADRENERGIC ANTAGONISTS- Beta Adrenergic Blockers

Question 1

• beta blockers end in…
• non selective vs selective/ cardioselective

Answer 1

-olol
can block b1 and b2 OR b1 selectivity

Question 2

beta adrenergic blockers are all…

Answer 2

competitive antagonists

Question 3

why are there not selective b2 antagonists?

Answer 3

there are no clinically useful B2 antagonists

Question 4

beta blockers main use

Answer 4

• lower blood pressure in hypertension
  NOT postural hypotension, bc the a adrenoceptors remain functional

-treat angina, cardiac arrhythmias, myocardial infarction, congestive heart failure, hyperthyroidism, and glaucoma
-serve in prophylaxis or migraines

prophylaxis- action to prevent disease

Question 5

NON-SELECTIVE B-adrenergic blockers

Answer 5

-propanolol
-nadolol and timolol

Question 6

PROPANOLOL:
- which receptors
- actions

Answer 6

• NON-selective (B1 and B2)
• CV: diminished cardiac output (B1)
• initial peripheral vasoconstriction (B2)
• bronchoconstriction (B2)
• DEC glycogenolysis and glucagon secretion

Question 7

propanolol: therapeutic uses/indications

Answer 7

• hypertension
• angina (dec O2 required)
• myocardial infarction (MI)
• migraine (prophylaxis, penetrates CNS)
• hyperthyroidism

Question 8

propanolol: adverse effects

Answer 8

• arrhythmias—> due to abrupt interruption of therapy, MUST taper drug
• bronchoconstriction (B2 in lung)—-> contraindication for COPD/asthma (needs selective B1)
• metabolic disturbances (hypoglycemia, inc low density lipoproteins)
• CNS effects—> lethargy, depression
• sexual impairment

Question 9

NADOLOL and TIMOLOL

Answer 9

• both MORE potent than propanolol
• timolol: treats chronic open-angle glaucoma
  ( B2 receptors on ciliary body muscles)

Question 10

when do we decide to use cholinergic agonists vs. beta blockers for glaucoma?

Answer 10

beta blockers are for chronic management, cholinergic agonists for EMERGENCY treatment of glaucoma

Question 11

SELECTIVE B1 ANTAGONISTS
- selectivity for which organ?
- list of drugs
- for which types of patients?

Answer 11

• cardioselective beta blockers
• good selectivity at LOW DOSES (if we inc dose it can act on B2 also REMEMBER!!!)

-for hypertensive PT’s with impaired pulmonary function or chronic stable angina

• acebutolol, atenolol, metoprolol, bisoprolol, betaxolol, esmolol

Question 12

why are selective B1 antagonists better for hypertensive patients with impaired pulmonary function or chronic stable angina?

Answer 12

B2 receptor activation causes bronchoconstriction which we DO NOT want to act on for patients with lung problems

Question 13

BETA ANTAGONISTS with PARTIAL agonist activity

Answer 13

• acebutolol: B1 selective antagonist
• pindolol: non-selective B blocker

Question 14

pindolol and acebutolol:
-actions
-therapeutic uses/indications

Answer 14

• can weakly stimulate both B1 and B2 (ISA= intrinsic sympathomimetic activity)
• less effect on lipid/carb metabolism
• B blockers with ISA effective in hypertensive PTs w moderate bradycardia (less effect on heart)
• NOT used for stable angina or arrhythmia ( bc partial agonist effect)

Answer 15

• Labetalol and carvedilol: non-selective B blockers, also BLOCK a1 actions
• so it’s useful for hypertensive PTs that undesire inc peripheral resistance, therefore decreases BP

NO INITIAL peripheral vasoconstrict

Question 16

labetalol and carvedilol: therapeutic uses

Answer 16

labetalol: alt to methyldopa in pregnancy induced hypertension
- IV for hypertensive emergencies (rapidly dec BP)

carvedilol: in PTs with stable chronic heart failure HF
- block SNS effects on heart

Question 17

labetalol and carvedilol: adverse effects

Answer 17

orthostatic hypotension and dizziness (a1 blockade)