Antiemetic and Antinausea Drugs Flashcards
What are the 6 types of Antiemetic drugs?
1) Anticholinergics
2) Antihistamines
3) Antidopaminergics
4) Prokinetics
5) Serotonin blockers
6) Tetrahydrocannabinoids
What is the mechanism of action of anticholinergics when used as an antiemetic?
As antiemetics, anticholinergics act by binding to and blocking ACh receptors in the vestibular nuclei, located deep in the brain. This prevents nausea-inducing signals from being transmitted to the vomit center.
What is the mechanism of action of an Antihistamine used as an antiemetic?
Antihistamine block histamine (H1) receptors and inhibit vestibular stimulation. This prevents the nausea signal from being transmitted to the vomit center (just like with anticholinergics).
What is the mechanism of action of Antidopaminergics and Prokinetics when used as an antiemetic?
They both block dopamine receptors in the CTZ, which desensitizes the CTZ to impulses it receives from the GI tract.
What is the mechanism of action of a Serotonin Blocker used as an antiemetic?
Serotonin blockers block serotonin receptors located in the GI tract, CTZ, and vomit center.
What is the mechanism of action of Tetrahydrocannabinol (THC) when used as an antiemetic?
THC has inhibitory effects on the reticular formation, thalamus, and cerebral cortex which causes an alteration in mood and and the body’s perception of its surroundings. This is beneficial in relieving nausea and Vomitting.
What are the 3 indications of Anticholinergics when used as antiemetics?
1) Motion sickness
2) Secretion reduction before surgery
3) Nausea and vomiting
What are the 6 indications of Antihistamines when used as antiemetics?
1) Motion sickness
2) Nonproductive cough
3) Sedation
4) Rhinitis
5) Allergy symptoms
6) Nausea and vomiting
What are the 3 indications of Antidopaminergics when used as antiemetics?
1) Psychotic disorders (mania, schizophrenia, anxiety)
2) Intractable hiccups
3) Nausea and Vomitig
What are the 3 indications of Prokinetics when used as antiemetics?
1) Delayed gastric emptying
2) Gastroesophageal reflux
3) Nausea and vomitig
What is the indication of Serotonin Blockers when used as antiemetic?
1) Nausea and Vomiting (associated with cancer chemotherapy and postoperative periods)
What are the 2 indications of Tetrahydrocannabinoids (THC) when used as antiemetics?
1) Nausea and Vomitting ( associated with cancer chemotherapy
2) Anorexia associated with weight loss in PTs with cancers and AIDS
Which class of antinausea drug presents an increased risk of tardive dyskensia in the young and elderly?
Prokinetic Drugs
What are the main adverse effects of antiemetic drugs?
1) CNS depression
2) Drowsiness
3) Dizziness
4) Hypotension (especially with THC)
