The Pharmacological Treatment of Nausea & vomiting Flashcards
Drugs for the management of motion sickness:
I. Anticholinergics:
II. H1 antihistamines:
Drugs for the management of motion sickness:
Anticholinergics: Drugs
SCOPOLAMINE: Is prophylactic only for motion sickness arising from short or long exposure to severe motion.
SCOPOLAMINE
Mechanism of action:
Cochlear (CN8) sensation of motion is projected via cholinergic fibers of the auditory nerve to the CTZ. Scopolamine is an anticholinergic that blocks the activation of muscarinic receptors by acetyl choline.
SCOPOLAMINE
Side effects:
sedation, extrapyramidal (drowsiness, dry mouth)
Drugs for the management of motion sickness
H1 antihistamines: Drugs:
- Ethanolamine derivatives: Dimenhydrinate (Dramamine™)
- Piperazines: Cyclizine & Meclizine
- Phenothiazine derivatives: Promethazine (Phenergan™)
Ethanolamine derivatives: Dimenhydrinate (Dramamine™) USE:
Available OTC for prophylaxis of MS. Taken 30-60 min prior to a trip & their effect last for 4-6 h.
Piperazines: Cyclizine &Meclizine USE:
- Cyclizine is OTC used primarily to counter MS.
- Meclizine, exerts a depressant effect on hyperstimulation of labyrinthine function. Used for vestibular Disturbances ( Vertigo & Menier’s disease).
- Phenothiazine derivatives: Promethazine (Phenergan™) USE:
Primarily used for the management of nausea & vomiting. Side effect: SEDATION.
ANTIDOPAMINERGICS AS ANTIEMETICS Classes:
A. Phenothiazines:
B. Butyrophenone derivatives
C. Benzamide derivatives
ANTIDOPAMINERGICS AS ANTIEMETICS
Mechanism of action:
They block dopamine receptors in the Chemoreceptor Trigger Zone (CTZ)
Phenothiazines: Drugs
- CHLORPROMAZINE
- PROCHLORPERAZINE
- THIETHYLPERAZINE
CHLORPROMAZINE
Action/Use:
• Is a centrally acting anticholinergic as well
as antidopaminergic.
• Used for N&V & intractable hiccough.
PROCHLORPERAZINE
Action/Use:
Is a poor antipsychotic but highly useful antiemetic .
THIETHYLPERAZINE
Action/Use:
Inhibits the CTZ & VC.
Butyrophenone derivatives
DROPERIDOL
• Blocks dopaminergic receptors in the CTZ. Clinically used
postoperatively for nausea and vomiting.