Emesis and migraines (Drugs)

Question 1

What are the anti-emetic drugs?

Answer 1

• Ondansetron
• Promethazine
• Scopolamine
• Aprepitant
• Metoclopromide

Question 2

What is the mechanism of action of ondansetron?

Answer 2

5-HT₃ antagonist (acts on CTZ)

Question 3

What is the mechanism of action of promethazine?

Answer 3

Histamine H₁ receptor antagonist (does not affect CTZ)

Question 4

What is the mechanism of action of scopolamine?

Answer 4

Non-selective muscarinic antagonist (acts in vestibular nuclei via M₁ receptors)

Question 5

What is the mechanism of action of aprepitant?

Answer 5

Neurokinin-1 receptor antagonist (acts on CTZ)

Question 6

What is the mechanism of action of metoclopromide?

Answer 6

Dopamine D₂ receptor antagonist (acts on CTZ)

Question 7

What are the drugs used to treat acute migrane attacks?

Answer 7

• Sumatriptan
• Naratriptan
• Ergotamine

Question 8

What is the mechansim of action of sumatriptan?

Answer 8

5-HT_1B/D/F agonist:

1. 5-HT_1B = Vasoconstrction
2. 5-HT_1D/F = Nociceptor inhibition

Question 9

What are the differences between sumatriptan and naratriptan?

Answer 9

Naratriptan:

• Crosses BBB
• Longer duration of action
• Fewer cardiac side-effects

Question 10

What are the drugs used to prevent migrane attacks (prophylaxis)?

Answer 10

• Propanolol (non-specific β-adrenoreceptor antagonist)
• Topiramate
• Methysergide (5-HT₂ antagonist)
• Botulinum toxin A

Question 11

What is the mechanism of topiramate?

Answer 11

• Anti-epilieptic
• Inhibits Na_vs and GABA_A receptors

Question 12

What is the mechanism of methylsergide?

Answer 12

5-HT₂ receptor antagonist