Adrenoreceptor Antagonists

Question 1

MoA of Alpha receptor blockers

Answer 1

Prevent the action of NE & E at the a receptors.

Question 2

Effects of Alpha receptor Blockers

Answer 2

1) ↓ TPR, ↓ mean BP.
2) May cause reflex tachycardia and salt and water retention

Question 3

Indication of Phentolamine

Answer 3

1. Pheochromocytoma
2. Antidote to overdose of α agonist
   (patients on MAO inhibitors who eat tyramine-containing foods & severe cocaine-induced hypertension)

Question 4

administration route of Phentolamine

Answer 4

Oral or IV.
–> Duration 2 – 4 h.
=->Short half life

Question 5

Adverse effects of phentolamine

Answer 5

1. Orthostatic hypotension.
2. Reflex tachycardia.

Question 6

category of Phentolamine and Phenoxybenzamine

Answer 6

Nonselective α receptors antagonist

Question 7

Indication of Phenoxybenzamine

Answer 7

1. Pheochromocytoma
2. carcinoid.
3. Mastocytosis.

Question 8

Administration route of Phenoxybenzamine

Answer 8

Oral
–> Long half-life of 24 – 48h.

Question 9

Adverse effects of Phenoxybenzamine

Answer 9

1. Orthostatic hypotension.
2. Reflex tachycardia.
3. GI irritation.

Question 10

Non-selective α-blockers

Answer 10

Phentolamine and Phenoxybenzamine

Question 11

Selective α1 receptor antagonists (drugs)

Answer 11

-osin
Prazosin, Doxaosin, Terazosin, Tamsoulosin

Question 12

indication of Selective α1 receptor antagonists
[Prazosin, Doxaosin, Terazosin, Tamsoulosin]

Answer 12

1. Benign prostatic hyperplasia (BPH)
   (bladder sphincter relaxation)
   (Decreases blood pressure –> Vasodilaion)
2. PTSD (Prazosin).
3. Miosis

Question 13

Administration of Selective α1 receptor antagonists
[Prazosin, Doxaosin, Terazosin, Tamsoulosin]

Answer 13

1. Prazosin –> 8 h duration.
2. Doxazosin, terazosin –> 12 – 24 h
   duration.
3. Tamsulosin –> approved for BPH

Question 14

Adverse effects of Selective α1 receptor antagonists
[Prazosin, Doxaosin, Terazosin, Tamsoulosin]

Answer 14

1. Orthostatic hypotension (1st does).
2. Little reflex tachycardia

Question 15

a drug that is a selective a2 receptor antagonist

Answer 15

Yohimbine

Question 16

Adverse effects of Yohimbine

Answer 16

1. Tachycardia.
2. GI upset.

Question 17

Administation route of Yohimbine

Answer 17

oral or parenteral.

Question 18

Indication of Yohimbine

Answer 18

erectile dysfunction

Question 19

MoA of Beta receptor blockers

Answer 19

Inhibit the action of catecholamines at beta receptors
- End in -olol

Question 20

Effects of Beta receptor blockers

Answer 20

1) β1 – blockade:
* ↓ HR, ↓CO, ↓ SV.
* ↓ renin release.

2) Cardioselectivity: (β1)
* Less effect on vasculature, bronchioles, uterus, and metabolism.
* Safer in asthma, diabetes, peripheral vascular diseases.

3) β2 – blockade;
* Respiratory effects;
–> May precipitate bronchospasm (in asthmatics)
–> Vasospasm (in patients with vasospastic disorders)

4) Effects on eye:
*↓ aqueous humor production.

5) Metabolic effects:
* Blocks glycogenolysis, gluconeogenesis &
↓ lipolysis (β3) [­↑ LDLs, ­ ↑ TGs]

Question 21

Νοn-selective β-blockers

Answer 21

Propranolol, Timolol

Question 22

Β1 selective blockers

Answer 22

Atenolol, Metoprolol

Question 23

Combined α + β-blocker

Answer 23

Labtalol, Carvedilol

Question 24

Indication of Propranolol

Answer 24

1) Angina
2) Arrythmia (tx and prophylaxis)
3)Hypertension
4) Thyrotoxicosis
5) tremor
6) Performance anxiety
7) migraine

Question 25

Administration route of Propranolol

Answer 25

Oral and IV –> Can enter CNS

Question 26

Adverse effects of Propranolol

Answer 26

Excessive β-block:
- Bronchospasm
- AV block
- HF
- CNS sedation, lethargy,
sleep disturbance

Question 27

Indication of Atenolol & Metoprolol?

Answer 27

Hypertension, Angina, Arrythmia

Question 28

Administration of Atenolol & Metoprolol?

Answer 28

Oral administration

Question 29

Adverse effects of Atenolol & Metoprolol?

Answer 29

1) Bronchospasm
2) Hypotension
3) Bradycardia
4) Heart failure
5) AV block
6) Respiratory Distress (allergic)

Question 30

Indication of Timolol

Answer 30

Glaucoma

Question 31

MoA of Timolol

Answer 31

↓AH formation
* AH: aqouea humour

Question 32

Indication of Labetalol

Answer 32

Hypertensive emergency

Question 33

Administration of Labtalol

Answer 33

Oral and IV

Question 34

Administration of Carvedilol

Answer 34

Oral and IV

Question 35

Indication of Carvedilol

Answer 35

Congestive Heart Failure