252 Pharmacology - Antiemetic Drugs Flashcards
Definition of nausea.
Sensation often leading to the urge to vomit
Definition of emesis (vomiting).
Forcible emptying of gastric and, occasionally, intestinal contents.
List the various classifications of antiemetic and antinausea drugs.
- Anticholinergic drugs
- Antihistamines (histamine 1 [H1] receptor blockers)
- Antidopaminergic drugs
- Neurokinin antagonists
- Prokinetic drugs
- Serotonin blockers
- Tetrahydrocannabinoids
What is the mechanism of action for most antiemetic or antinausea drugs?
Most work by blocking one of the vomiting pathways, thus blocking the stimulus that induces vomiting.
What is the mechanism of action for anticholinergic antiemetiic/antinausea drugs?
- Bind to and block acetylcholine receptors in the inner ear labyrinth
- Block transmission of nauseating stimuli to CTZ
- Also block transmission of nauseating stimuli from the reticular formation to the vomiting centre
Define chemoreceptor trigger zone (CTZ)
The area of the brain that is involved in the sensation of nausea and the action of vomiting.
What is the vomiting centre (VC)?
The area of the brain that is involved in stimulating the physiological events that lead to nausea and vomiting.
What are the indications for anticholinergics?
- Motion sickness
- secretion reduction before surgery
- nausea and vomiting
What are the indications for antihistamines?
- Motion sickness
- Nonproductive cough
- Sedation
- Rhinitis
- Allergy symptoms
- Nausea and vomiting
What are the indications for antidopaminergics?
- Psychotic disorders
- intractable hiccups
- nausea and vomiting
What are the indications for prokinetics?
- Delayed gastric emptying
- Gastroesophageal reflux
- Nausea and vomiting
What are the indications for serotonin blockers?
- Nausea and vomiting associated with chemotherapy
- Postoperative nausea and vomiting
What are the indications for tetrahydrocannabinol?
- Nausea and vomiting associated with chemotherapy
- Anorexia associated with weight loss in patients with AIDS and cancer
What are some causes of N and V?
- Chemotherapy
- Postoperative
- Anesthesia
- General
- Inner ear infection
What class is scopolamine?
anticholinergic
What is the mechanism of action of anticholinergic antiemetics?
- Bind to and block acetylcholine receptors in the inner ear labyrinth
- Block transmission of nauseating stimuli to CTZ
- Also block transmission of nauseating stimuli from the reticular formation to the vomiting centre