Sympathetic Pharmacology

Question 1

What types of drugs affect sympathetic activity?

Answer 1

Agonists, antagonists and indirectly acting sympathomimetics

Question 2

alpha-1 receptors - where are they and what affect do they have?

Answer 2

Smooth muscle, bladder. For contraction (noradrenaline)

Question 3

alpha 2 - where and action?

Answer 3

CNS. Inhibition of noradrenaline and sympathetic NS (noradrenaline)

Question 4

beta-1 - where and action

Answer 4

Heart, increase HR, contractility (noradrenaline)

Question 5

beta-2 - where and action

Answer 5

Smooth muscle, bronchial. Relaxation (adrenaline

Question 6

Directly acting sympathomimetics - what are the therapeutic uses? E.g. adrenaline

Answer 6

ANAPHYLATIC SHOCK - symptoms due to degranulation of mast cells (histamine release = bronchospasm) and peripheral vasodilation = hypotension.
BRONCHIAL ASTHMA - inflammation of air passages. Medication affects smooth muscle - dilate bronchi, mimic sympathetic bronchodilation by inhalation of beta-2 adrenoceptor agonist salbutamol

Question 7

Give examples of indirectly acting sympathomimetic drugs

Answer 7

NA reuptake inhibitors, cocaine and amphetamine

Question 8

How do Tricyclic Antidepressants work (NA reuptake inhibitor)

Answer 8

Enhances NA in brain, block reuptake - heightened sympathetic excitation = tachycardia, vasoconstriction, hypertension

Question 9

How does cocaine work?

Answer 9

Addictive CNS stimulants (inhibits DA uptake and blocks reuptake of NA) - same as TCAs

Question 10

How does amphetamine work?

Answer 10

Causes exocytotic NA

Question 11

Use of adrenoceptor agonists

Answer 11

ISCHAEMIC HEART DISEASE - reduces cardiac load during heart beat (block sympathetic tone - beta-1 antagonist PROPRANOLOL - non-selective beta blocker)

Question 12

Beta-blocker - can be contraindicated, how do we overcome this problem?

Answer 12

antagonist selective at beta-1 only = ATENOLOL - it is cardiac selective but not cardiac specific

Question 13

Beta blockers are generally contraindicated to asthmatic with what?

Answer 13

IHD

Question 14

What are the therapeutic uses of alpha - 1 adrenoceptor antagonists?

Answer 14

Hypertension - inhibits alpha adrenoceptors vasoconstriction and promote vasodilation
Benign Prostatic Hypertrophy - (disorder bladder function) inhibiting alpha adrenoceptors improves bladder emptying

Question 15

What is the major side effect of using alpha-1 adrenoceptor antagonists

Answer 15

PASTURAL HYPOTENSION - decr in relex vasoconstriction that occurs when standing up and decr in bp = dizziness and fainting when standing up