Sketchy Pharm: Antiemetic Agents Flashcards
The nucleus solitarius receives input from the ______________.
GI tract, vestibular system, and area postrema
The nucleus solitarius sends out what?
Axons to other areas to coordinate the vomiting response
What nerve mediates the vomiting response?
The vagus nerve (think of the neon sign in the stomach-shaped dirt area advertising fabulous Las Vagus)
By what molecular/nerve mechanism does GI irritation lead to the vomiting response?
Stomach irritation induces release of serotonin by gastric cells onto the 5HT-3 receptors of the vagal afferents. (Think of the athlete releasing the smiley face by the 1-2-3 Hammer Throw sign.)
Which system is responsible for motion sickness and vertigo?
The vestibular system (think of the rower with the orange VEST vomiting)
Where is the area postrema located?
The area postrema (also called the chemoreceptor-trigger zone) is next to the nucleus solitarius in the 4th ventricle –it is not protected by the BBB.
Ondansetron blocks ____________.
5HT-3 receptors on the vagal nerve
Although ondansetron is generally well tolerated, what are the most common side effects?
Constipation (think of the runner with the serotonin cord wrapped around the runners gut); headache (think of the serotonin ball hitting the other runner); QT prolongation; and serotonin syndrome (with concomitant SSRI use).
What part of the vomiting response do antihistamines block?
The vestibular response (H1 receptors –Gq receptors)
Which muscarinic receptor isotype do antimuscarinics act on when they counteract the dizziness response?
M1 (the M1 motorcycle) in the vestibular system
__________ receptors are also on the area postrema.
D2 receptors
Which drugs block the D2 receptors of the area postrema?
Metoclopramide (think of the guy TiCkLing the gymnast on the rings)
What is a potentially useful side effect of metoclopramide?
Treatment of non-obstructive ileus due to prokinetic effect on the GI tract (think of the gymnast falling on the stomach pad)
The non-useful side effects of metoclopramide include _________________.
extrapyramidal side effects, depression, neuroleptic malignant syndrome, prolactinemia, and somnolence (from central D2 blockade)
Those with neuroleptic malignant syndrome can have elevated levels of ________________.
creatine kinase
