Drugs In Adrenergic Pharm Flashcards
NA and A belong to a class of compounds known as ____.
Catecholamines
What is isoproenaline
It is a synthetic derivative of noradrenaline
Function of NA
- activates a2 pre-synaptic receptor —> negative feedback to inhibit tyrosine hydroxylase
- can bind to other alpha and beta receptors
Main action and ADR of sabutamol
- B2 agonist
- treats asthma
- ADR: peripheral vasodilation, dysrhythmias, tachycardia, tremor
Main action and ADR of phenylephrine
- a1 agonist
- treats nasal congestion: phenyl (smell)
- ADR: hypertension, reflex bradycardia due to sudden increase in cardiac output due to vasoconstriction
Main action and ADR of clonidine
- 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)
Main action of propranolol
- 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
ADR of propranolol
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)
Alpha-methyl-p-tyrosine
Inhibits tyrosine hydroxylase from converting L-tyrosine into L-DOPA
Reserpine
Inhibits VMAT (vesicular monoamine transporter) from transporting NA into vesicles for storage
Amphetamine/ephedrine/tyramine
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
Cocaine
- Inhibits NET
- decreases reuptake of NA and other neurotransmitters such as serotonin and dopanine into presynaptic terminals
- increase sympathetic activity
Moclobemide
- Inhibits MAO
- increases availability of neurotransmitters like NA
- anti-depressant
Function of adrenaline in treating anaphylaxis
Adrenaline decreases the release of mediators (histamine) from mast cells