Serotonin Agonists and Antagonists

Question 1

Serotonin is produced from?

Answer 1

Tryptophan

Question 2

Serotonin is metabolised by?

Answer 2

Monoamine oxidase

Question 3

Major metabolite of serotonin

Answer 3

5-Hydroxyindoleacetic acid (5-HIAA)

Question 4

5-HT1 receptors are present in? And their function

Answer 4

Brain and they mediate synaptic inhibition

Question 5

5-HT2 receptors are present in? And their function

Answer 5

Brain and peripheral tissues
Mediate synaptic excitation in the CNS or smooth muscle contraction
Reduction in appetite (5-HT2c)

Question 6

5-HT3 receptors are present in? And their function

Answer 6

CNS (chemoreceptive area & vomiting center)
Mediate excitation

Question 7

5HT-3 receptors are present in? And their function

Answer 7

CNS (chemoreceptive area & vomiting centre)
Mediate excitation

Question 8

5-HT4 receptors are present in? And their function

Answer 8

GI tract
mediate intestinal motility

Question 9

Sumatriptan clinical use?

Answer 9

First line treatment for acute migraines and cluster headaches attack

Question 10

5-HT2c agonist names?

Answer 10

Lorcaserin
Fenfluramine
Dexfenfluramine

Question 11

Lorcaserin clinical use?

Answer 11

Treat obesity

Question 12

5-HT4 partial agonist name?

Answer 12

Tegaserod

Question 13

Tegaserod clinical use

Answer 13

Chronic constipation (now restricted b/c of cvs toxicity)

Question 14

Selective serotonin reuptake inhibitors (SSRI) clinical use

Answer 14

Antidepressants

Question 15

Serotonin syndrome?

Answer 15

Elevated serotonin levels
-hyperthermia, hyperreflexia, tremor, clonus, htn, hyperactive bowel sounds, diarrhoea, mydriasis, agitation, coma

Question 16

Serotonin syndrome first line drug management

Answer 16

Sedation (benzodiazepines)
Paralysis
Intubation
Ventilation

Question 17

5-HT2 blockers

Answer 17

Ketanserin
Phenoxybenzamine
Cyproheptadine

Question 18

5-HT3 blockers

Answer 18

Ondansetron
Granisetron
Dolasetron
Alosetron

Question 19

Ketanserin clinical

Answer 19

Antihypertensive

Question 20

Drugs for carcinoid tumor (high levels of serotonin)

Answer 20

Ketanserin, cyproheptadine and phenoxybenzamine (mono or in combination)

Question 21

Ondansetron clinical use

Answer 21

Chemotherapy induced vomiting and post op. vomiting

Question 22

Alosetron clinical use

Answer 22

IBS with diarrhoea in women

Question 23

Ketanserin toxicity

Answer 23

-Dizziness, headache and orthostatic hypotension due to alpha blockade
-Dry mouth, dry eyes, blurred vision and hypotension due to H1 blockade

Question 24

Dolasetron toxicity

Answer 24

QRS & QTc prolongation