Drugs In Adrenergic Pharm

Question 1

NA and A belong to a class of compounds known as ____.

Answer 1

Catecholamines

Question 2

What is isoproenaline

Answer 2

It is a synthetic derivative of noradrenaline

Question 3

Function of NA

Answer 3

• activates a2 pre-synaptic receptor —> negative feedback to inhibit tyrosine hydroxylase
• can bind to other alpha and beta receptors

Question 4

Main action and ADR of sabutamol

Answer 4

• B2 agonist
• treats asthma
• ADR: peripheral vasodilation, dysrhythmias, tachycardia, tremor

Question 5

Main action and ADR of phenylephrine

Answer 5

• a1 agonist
• treats nasal congestion: phenyl (smell)
• ADR: hypertension, reflex bradycardia due to sudden increase in cardiac output due to vasoconstriction

Question 6

Main action and ADR of clonidine

Answer 6

• a2 partial agonist
• inhibits NA release
• treats hypertension, migraine
• ADR: drowsiness, headache, dizziness (a1, vasodilation —> low bp), constipation (B2, relaxing colon muscles), bradycardia (B1, reducing cardiac output)

Question 7

Main action of propranolol

Answer 7

• non-selective B antagonist
• treats angina, hypertension, cardiac dysrhythmias, anxiety, tremor, glaucoma, claims to be an aphrodisiac

** Footnote:
Angina: chest pains, propranolol slows HR and reduce oxygen demand for heart to reduce chest pains
Hypertension: target B1 receptors to decrease cardiac output by decreasing renin release

Question 8

ADR of propranolol

Answer 8

Bronchoconstriction: B2 antagonist
Cardiac failure
Cold extremities: B2 antagonist —> vasoconstriction, less blood flow
Fatigue
Depression: propranolol can cross BBB
Hypoglycaemia: blocks B2 receptors in liver (conversion of glycogen to glucose)

Question 9

Alpha-methyl-p-tyrosine

Answer 9

Inhibits tyrosine hydroxylase from converting L-tyrosine into L-DOPA

Question 10

Reserpine

Answer 10

Inhibits VMAT (vesicular monoamine transporter) from transporting NA into vesicles for storage

Question 11

Amphetamine/ephedrine/tyramine

Answer 11

Increase NA synthesis

**Footnote:
Amphetamines have structural similarity to NA and are taken up by NET and VMAT instead of NA
Amphetamines have some inhibitory effect on MAO
Tyramine is derived from chocolates, cheese and wine
Ephedrine has the same effect as amphetamines

Question 12

Cocaine

Answer 12

• Inhibits NET
• decreases reuptake of NA and other neurotransmitters such as serotonin and dopanine into presynaptic terminals
• increase sympathetic activity

Question 13

Moclobemide

Answer 13

• Inhibits MAO
• increases availability of neurotransmitters like NA
• anti-depressant

Question 14

Function of adrenaline in treating anaphylaxis

Answer 14

Adrenaline decreases the release of mediators (histamine) from mast cells