Ch 10: Adrenergic Blockers

Question 1

Adrenergic Blockers (Sympatholytics)

Answer 1

1. Alpha-1 blockers:
   phenoxylbenzamine, prazosin, terazosin
   - For hypertensive crisis, high catechize hypertension, some migraines
   ** Inhibits vasoconstriction, allows Beta-induced vasodilation
2. Alpha-2 blockers:
   yohimbine (phentolamine is non-selective… alpha-1 = alpha-2)
   - allows increased NE from terminals (only used experimentally)

Question 2

Phentolamine

Answer 2

• blocks aplha-1 adrenoceptors

- epinephrine activated both alpha and beta receptors

Question 3

Beta Blockers

Answer 3

1.
Beta-1: metoprolol, atenolol
- slows HR, reduces contractility, inhibit renin
* For: arrhythmias, hypertension, heart failure, anxiety
Side effects: bradycardia, B-receptor super-sensitivity

2. B-1 = B-2: propanolol, nadolol, timolol
   - labetolol (also blocks alpha receptors)

3.
B-2: butoxamine –> No therapeutic indications
- B-2 blocking can cause bronchoconstriction (no asthmatics) and inhibit glycogenolysis (no diabetics)

Question 4

Cardiac effects of Beta-Blockers

Answer 4

• decrease contractility (negative inotrophy)
• decrease relaxation rate (negative chronotrophy)
• decrease heart rate (negative chronotrophy)
• decrease conduction velocity (negative dromotrophy)

Question 5

Vascular effects of Beta-Blockers

Answer 5

• smooth muscle contraction (mild vasoconstriction)

Question 6

Action- Blocks Beta receptors in the Heart causing:

Answer 6

decrease in heart rate
decrease in force of contraction
decrease in rate of A-V conduction

Question 7

Side effects of B-Blockers

Answer 7

bradycardia
lethargy
GI disturbance
CHF
decrease in BP
depression

Question 8

Abuse of Beta-blockers in sports

Answer 8

• calm down heart beat and circulation
• avoid excitement, stage fright and Hand tremor
  
  • ***** increased tranquilization

Question 9

Side effects of Adrenergic Antagonists B-Blockers

Answer 9

Hypotension
symptoms in CHF
bradycardia (AV-block)
drowsiness, depression

Question 10

Adrenergic transmission blockers

Answer 10

1. Reserpine
   - depletes catechize stores by blocking uptake; causes transient sympathomimetic effect, then sympatholytic.
   For hypertensive crisis/ hypertension
   - can cause lethargy and depression
2. Guanethidine
   - taken up then prevents NE release; leads to prolonged hypotension
   - can cause hypotension, bradycardia, sexual dysfunction
3. Guanadrel
   - similar to guanethidine, but also blocks NE release from adrenal medulla