Alpha and beta agonists/antagonists

Question 1

Alpha-agonists main effect

Answer 1

Vasoconstriction

Question 2

Beta-agonists main effect

Answer 2

Bronchodilation

Question 3

Alpha-antagonists main effect

Answer 3

Vasodilation

Question 4

Beta-antagonists main effect

Answer 4

Cardioprotection - reduces effects of nor/adr

Question 5

Alpha 1 agonists uses

Answer 5

Raise BP in shock and reduce blood flow during surgery
Relieve nasal congestion - constricting blood vessels
E.g. Noradrenaline, pseudoephedrine ‘sudafed’, xylometazoline ‘otrivin’
*caution with pts with HTN using decongestants

Question 6

Alpha 2 agonists

Answer 6

Increases reuptake of released noradrenaline
Used in HTN
E.g. clonidine

Question 7

Beta agonists (non-selective)

Answer 7

Activating both beta 1 and 2 receptors
Bronchodilation, vasoconstriction, tachycardia
e.g. isoprenaline (non-selective beta agonist)

Question 8

Beta 2 agonists

Answer 8

Selective stimulation of B2 receptors
Bronchodilation
Used in asthma, COPD + delay prem labour, treat hyperkalemia
e.g. salbutamol, salmeterol

Question 9

Beta 1 agonists

Answer 9

Selective beta 1 receptors
Predominantly on myocardium
Used for inotropic support in infarction, cardiac surgery
e.g. dobutamine, dopexamine

Question 10

Alpha 1 antagonists

Answer 10

Used in HTN - peripheral artery dilation - block effects of noradrenaline
Not first line for HTN
Used in pts with poor circulation (frostbite, raynauds disease)
E.g. doxazosin, taerazosin, tamsulosin

Question 11

Beta antagonists ‘beta blockers’

Answer 11

Reduce sympathetic tone - esp HR
Used in HF, post MI, angina
Non-selective - propanalol, carvedilol
Cardioselective - more B1 - atenolol, metoprolol, bisoprolol