Adrenergic Antagonists & Receptors

Question 1

Adrenergic antagonists are divided into

Answer 1

a and b blockers

Question 2

a blockers are further divided into

Answer 2

non-selective and selective

Question 3

Under non-selective a blockers, it is further divided into

Answer 3

Reversible : PHENTHOLAMINE
Irreversible: PHENOXYBENZAMINE

Question 4

Alpha 1 blockade causes

Answer 4

Vasodilation (decrease in BP)

Question 5

Alpha 2 blockade causes

Answer 5

Tachycardia

(No longer inhibit NA release, hence HR increases)

Question 6

Treatment of PHEOCHROMOCYTOMA

Answer 6

Phenoxybenzamine
-control hypertension due to increased catechololamines
-cause postural hypotension , tachycardia, nasal stuffiness

Question 7

Alpha 1 antagonist causes

Answer 7

Vasodilation in arteries and veins
Peripheral resistance decreases
BP decreases

If there’s only arterial dilation NO POSTURAL HYPOTENSION

Question 8

Alpha 2 antagonist causes

Answer 8

Increase in A & NA
Increase in sympathetic outflow
Tachycardia
Increase in insulin
Increase in urine outflow in BPH
Decrease smooth muscle tone in prostate & bladder
Increase miosis ( pupil constriction)

Question 9

In selective alpha antagonists, there are

Answer 9

Prazosin a1
Yohimbine a2
Ergot alkaloids (miscellaneous)

Question 10

Treatment of hypertension

Answer 10

Prazosin
(Therapeutic uses: systemic hypertension & BPH)
(ADR: first dose hypotension, orthostatic hypotension)

Question 11

Treatment for BPH

Answer 11

tamsulosin (most preferred)
2nd choice: Prazosin

Question 12

Duration of effect for non-selective alpha blockers?

Answer 12

Phentolamine (reversible): short lasting
Phenoxybenzamine (irreversible): long lasting

Question 13

Adrenergic beta blockers include

Answer 13

Non-selective no ISA (propranolol)
Non-selective ISA (pindolol)
Selective b1 no ISA (metaprolol)

a+b blockers (labetolol)

Question 14

B Non selective no ISA blocker, propranolol ‘s effects

Answer 14

Block sympathetic tone, decrease HR CO Pacemaker activity & PR.
Increase oral secretion
Lipophilic can cross BBB - cause drowsiness
Extensive 1st pass metabolism

Question 15

Propranolol’s (lipophilic) therapeutic uses

Answer 15

Hypertension= b blockers reduce HR, contractility & CO which in turn produce antihypertensive effects->vasodilation (indirect)
hyperthyroidism (tremors)
Migraine
Prophylaxis
Glaucoma

In short, it blocks sympathetic tone, lowering HR & CO, lowering PR.
Makes patients drowsy
Extensive 1st pass metabolism

Question 16

ADR of propranolol

Answer 16

In diabetes: prevent hyperglycaemia response like tachycardia

Sudden withdrawal syndrome: rebound hypertension

Question 17

Contraindication of propranolol

Answer 17

asthma & COPD :bronchoconstriction due to b2 blockage
decompensated heart failure
heart block
cardiogenic shock

Question 18

Beta blockers (CVS effects)

Answer 18

antihypertensive effect: Decrease in HR, contractility, renin (long term) => decrease in TPR
In conditions like: hypertensive: decrease in BP , vasodilation
antiarrhythmic: decrease in sinus rate, conduction, ectopic pacemaker activity
anti-ischaemic: decrease cardiac work, decrease O2 demand
congestive cardiac failure: decrease in sympathetic tone

Question 19

Beta blockers (pharmacological action)

Answer 19

Inhibit lipolysis
Block adrenaline induced hyperglycaemia
Decrease IOP
Increase tremor
CVS effects: sedation

Question 20

Selective b1 blocker no ISA, metoprolol’s effects

Answer 20

Less risk in bronchoconstriction
Less risk in metabolic abnormalities
Increase tremors

Question 21

Non-selective ISA b blocker, pindolol’s effects & uses

Answer 21

Decrease withdrawal

For Bradycardia/bronchial asthma
Not for ischemic heart

Question 22

a+b blocker, labetolol’s effects & uses & contraindications

Answer 22

Decrease systemic arterial BP, decrease vascular resistance

For pregnancy induced hypertension

Contraindication:
asthma & COPD:bronchoconstriction due to b2 blockage
decompensated heart failure
heart block
cardiogenic shock

Question 23

Patient is in 3rd trimester of pregnancy , she presents strong contraction, which adrenergic agonist is used to delay the labour?

Answer 23

Ritidrine (acts on b2= uterine relaxation)