ANTI EMETICS Flashcards
What is nausea?
An unpleasant sensation of abdominal discomfort accompanied by a desire to vomit.
What is vomiting?
The expulsion of stomach contents through the mouth often linked to nausea.
What stimulates the vomiting center in the medulla oblongata?
Dopamine and acetylcholine.
What is the purpose of vomiting as a mechanism?
It is protective triggered by noxious stimuli to remove harmful substances.
What are emetics?
Drugs used to induce vomiting typically in cases of poisoning with non-corrosive agents.
What is the active ingredient in ipecac syrup? .
Emetine
How does emetine induce vomiting?
By direct irritation of the upper gut and by stimulating the chemoreceptor trigger zone (CTZ) in the medulla.
What are adverse effects of emetics?
Prolonged vomiting aspiration
What are antiemetics?
Drugs used to relieve nausea and vomiting by acting on the vomiting center CTZ
Which is more effective: prophylaxis or treatment with antiemetics?
Prophylaxis is generally more effective.
What are phenothiazines?
Neuroleptics such as chlorpromazine that block dopamine receptors at the CTZ and vomiting center.
What are indications for phenothiazines?
Nausea and vomiting induced by drugs radiation therapy
What is a common side effect of antihistamines?
Drowsiness especially troublesome for travelers.
What is metoclopramide?
A drug with central and peripheral antiemetic effects.
What is the central mechanism of metoclopramide?
It antagonizes dopamine in the CTZ.
What is the peripheral mechanism of metoclopramide?
It stimulates acetylcholine release increasing gastric emptying (useful in GERD).
What is the bioavailability of metoclopramide?
IM: 74-96% PO: 65-95%.
What is the onset time for metoclopramide?
IV: 1-3 min IM: 10-15 min
What is scopolamine?
An anticholinergic drug effective for motion sickness-induced nausea and vomiting.
What is ondansetron?
A serotonin antagonist (5-HT3) effective in controlling chemically induced nausea and vomiting.
Where are 5-HT3 receptors found?
On afferent vagus nerve fibers and parts of the brain associated with the CTZ.
What is the primary use of ondansetron?
To control nausea and vomiting induced by chemotherapy surgery
