Autacoid

Question 0

Allergic reaction

Answer 0

Conjunctivitis

Rhinitis

Triple response:
Red spot: Vasodilation
Wheal: Increased capillary permeability
Flare: Axon reflex and sensory nerve stimulation

Question 1

Histamine

Answer 1

Histidine

MAO

Receptor: G protein coupled

Mast cell, basophils, stored in actively in secretory granules

Degranulation: immunologic release( sensitising IgE to surface of mast cell, react with specific antigen which results in Ab:at complex), tissue injury, compound eg bradykinin. Slow turnover

Non mast cell( ecl like in stomach)

Synthesised and released upon stimulation. Rapid turnover

Question 2

Loratadine

Answer 2

H1

Orally

Rapid onset

SE: drowsiness, headache, dry mouth

Question 3

Levocabastine

Answer 3

H1

Eye drops, nasal spray

Potent, fast

Question 4

Olopatadine

Answer 4

H1

Eye drop

Mast cell stabiliser

Inhibit immediate hypersensitivity reaction

Question 5

Serotonin

Answer 5

EC cell, platelet, brain

Only 5-HT3 ligand gated channel

Peripheral action:
Stimulate nociceptive nerve endings and complex cardiovascular

Gut:
Increase gut motility, direct effects on SM

Platelet and vascular:
Platelet aggregation
Vasodilation ( endothelium)
Vasoconstriction ( SM)

Question 6

Sumatriptan

Answer 6

5-HT1D agonist

Constrict large arteries and inhibit trigeminal nerve transmission

SE: coronary vasoconstriction

For first few couple hours

(Dihydroergotamine- anytime)

Question 7

Methysergide

Answer 7

5-HT2 antagonist

Prophylactic

Question 8

Ondansetron

Answer 8

5-HT3 antagonist

Inhibit 5HT released from intestinal EC cells, initiating a vomiting reflex by activating bagel afferents -> vomit centre

Question 9

Fluoxetine

Answer 9

Selective serotonin re uptake inhibitors

Anti depressant

Question 10

Pricalopride

Answer 10

5-HT4 agonist

Anti constipation

IBS - constipation, diarrhoea, alternating