Antiemetics Flashcards
Where is the vomiting center that consists of the nucleus of tractus solitarius and parts of the reticular formation?***
Emesis controlled by vomiting center which lies in the (medulla oblongata)*** which consists of the nucleus of the tractus solitarius and parts of the reticular formation.
What detects noxious chemicals in the blood stream that is cephalad to the vomiting center?***
Cephalad to vomiting center is the CRTZ (Chemoreceptor trigger zone)*** which detects noxious chemicals in blood stream
Which cranial nerves sends signals through the vagal parasympathetic fibers upon activation of the vomiting centers?**
Activation of the vomiting center sends signals via (cranial nerves V, VII, IX, X, and XII)*** through vagal parasympathetic fibers and the sympathetic chain to the skeletal muscle through alpha motor neurons
What six receptors will stimulate efferent signals via cranial nerves to the vomiting center? ***
Dopamine Serotonin Substance P Acetylcholine GABA Cannabinoids
Where is the exact location of the Chemoreceptor trigger zone (CTZ)?**
At the base of Fourth ventricle in area of Postrema*****
What is makes the Chemoreceptor trigger zone (CTZ) unique? ***
Very vascular and lacks blood brain barrier.**
Because its location and exposure it can be directly stimulated by toxins, metabolites, and drugs that circulate in the blood and cerebrospinal fluid.
How does scopolamine work? What receptors?***
Competitive antagonist of AcH at (muscarinic receptors) and the MOST effective single agent for prevention of motion
What class of drug is scopolamine?
Anti cholinergics
Acetylcholine involved in integrating sensory stimuli in the vestibular nuclei and transmitting expected sensory information to the cerebellum.
Does atropine cross the BBB?**
Yes
What is the exact MOA of Scopolamine??***
MOA- blocks transmission to the medulla due to overstimulation of vestibular apparatus of the inner ear
Where does Metocolpraminde directly effect? **
CTZ
Does Metoclopramide (Reglan) cross the BBB?
Yes
What other effects does Metoclopramide (Reglan) have?
Other than effecting the CTZ it also has antidopaminergic effects
How does Midazolam work on the CTZ?***
May decrease synthesis and release of dopamine within the CRTZ*
GABA Agonist
What is the MOA of Midazolam??
GABA receptor mediated reduction of dopamine and 5HT3 receptor activity in the CTZ
What is the black box warning for Droperidol?
black box warning prolonged QT syndrome*
What class of drug is Droperidol?
Dopamine Antagonists
Butyrophenones
Which drug is considered an efficient rescue drug for PONV? Droperidol or Haloperidol?
Droperidol
Which drug is an antiemetic when used in low doses and used in Psych with high doses?
Haloperidol (Haldol)
What is the adult dose for Droperidol (inapsine)?**
Adults 0.625-1.25 mg
What is the peds dose for Droperidol (Inapsine)?***
Peds 50-75 mcg/kg
How does Droperidol (Inapsine) work?***
Binds to D2 receptors/antagonizes; also alpha-blocker