Serotonin Agonists & Antagonists Flashcards
The amino acid precursor of Serotonin is?
Tryptophan
Site of Serotonin Synthesis in the CNS?
Raphe nuclei of the brain stem.
List 3 drugs classified under 5HT1 Receptor agonists.
BET
* Buspirone
* Ergotamine - partial
* Triptans
List 2 examples of drugs classified under 5HT1 Receptor Antagonists.
- Spiperone
- Methiothepin
What is the major drug that functions as a 5HT2 receptor agonist?
Lysergic Acid Diethylamide ( LSD)
State 5 major drugs under 5HT2 receptor antagonists.
- Pastor - Pizotifen
- Ken - Ketanserin
- Made - Methysergide
- Christians - Cyproheptadine
- Pray - Phenoxybenzamine
- Religiously - Ritanserin
What is the mechanism by which 5HT3 receptors effects are mediated ?
Mediated through direct receptor coupled ion channels.
State one major 5HT3 receptor agonist.
2- Methyl- 5HT
List down 5 major 5HT3 receptor antagonist drugs.
DAGOT
D- Dolasetron
A- Alosetron
G- Granisetron
O- Ondansetron
T- Tropisetron
Major drugs used as a 5HT4 receptor agonist?
- Metoclopramide
- Tegaserod - partial agonist
State one major clinical application of Tegaserod.
Used in treatment of irritable bowel syndrome and constipation.
* NB- its use is restricted due to CVS toxicity.
State the major drugs classified under 5HT4 receptor antagonists.
CRAM
* Cisapride
* Renzapride
* Alosetron ( but mainly 5HT3)
* Metoclopramide - but is mainly a D2 antagonist
List 3 drugs commonly used in treatment of Carcinoid tumor.
- Ketanserin
- Cyproheptadine
- Phenoxybenzamine
State one major clinical application of 5HT3 receptor antagonists.
- Antiemetic effects - use to prevent nausea and vomiting e.g post surgery or in patients undergoing cancer chemotherapy.
- Inhibit emetic action at the area postrema of the medulla .
E g Ondansetron, Granisetron & Dolasetron.
The most important receptor involved in cytotoxic drug induced vomiting is ?
Serotonin 5HT3 receptor.
The most effective antiemetic drug for controlling cisplatin induced vomiting is?
Ondansetron
Cisapride enhances gastrointestinal motility by ?
Activating serotonin 5HT4 receptors.
State the major clinical manifestations associated with Serotonin Syndrome.
SHIVERS
S- Shivering
H- Hyperreflexia+ myoclonus
- Hypertension
- Hyper active bowel sounds
I- Increased temperature ( hyperthermia)
V- Vital Signs Instability
E- Encephalopathy
R- Restlessness
S- Sweating
What are the therapeutic steps recommended in a patient with Serotonin Syndrome?
- Sedation using benzodiazepines.
- Intubation & ventilation if paralyzed .
- 5GT2 receptor blockers with Cyproheptadine & Chlorpromazine.
Which drug causes cardiac arrhythmias when used by patients taking the gastrointestinal promotility agent Cisapride?
Ketoconazole
GIT drug associated with the long QT syndrome and cardiac arrhythmias?
Cisapride
Outline the major groups of drugs used in treatment of migraines.
- Triptans e.g sumatriptan .
- Ergot Alkaloids
- NSAIDS analgesic agents e.g ibuprofen.
- B- adrenoceptor blockers
- Calcium channel blockers e.g propranolol
- Tricyclic antidepressants
- SSRIS
- Anti seizure agents e.g Valrpoic acid & topiramate.
