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Pharm1152-Antiemetic
Antiemetic/Antinausea drugs
Question | Answer |
---|---|
Antiemetic drugs are used to releive ? by blocking signals to ? | nausea and vomiting; chemoreceptors |
3 Parts of body that are conected to chemoreceptor trigger zone which causes vomiting (medulla) | Gastrointestinal tract, Labryinth (inner ear), cerebral cortex |
Antiemetics and Antinausea drugs mechanism of action | many different, most work by blocking one of the vomiting pathways, thus blocking the stimulus that induces vomiting |
GI tract pathways (2) | Prokinetic drugs, Serotonin drugs |
Labryinth (inner ear) pathways (4) | Anticholingerics, antihistamine, antidopamingerics, prokinetic drugs |
Cerebral cortex pathways (3) | THC, Corticosteroids, Benzodiazepines |
General use for each type of antiemetic/antinausea drugs: | prevention and reduction of N/V |
Mechanism of action: Anticholinergic drugs(ACh blockers) | Bind to and block acetylcholine (ACh receptors) in the inner ear labyrinth, block transmission of nauseating stimuli to CTZ and of nauseating stimuli from the reticular formation to the VC(vomiting center) |
Example of Anticholinergic drug | Scopolamine (motion sickness)- transdermal patch beind ear (blocks ACh in ear to CTZ) |
Mechanism of action: Antihistamine drugs (H1 receptor blockers) | Inhibit ACh by binding to H1 recptors, prevent cholinergic stimulation in vestibular and reticular areas, thus preventing N/V |
Antihistamine drugs are also used for: (4) | motion sickness, nonproductive cough, allergy symptoms, sedation |
Examples of Antihistamine drugs (3) | Dimenhydrinate (Dramamine), diphenhydranube (benadrayl), meclizine (Antivert) |
Mechanism of action: Antidopaminergic drugs | Block dopamine receptors on the CTZ, also used for psychotic d/o, intractable hiccups |
Examples of Antidopaminergic drugs (3) | prochlorperazine (compazine), promethazine (Pheragan), droperidol (Inaspine)- controversial due to cardiac dysrhytmia |
Mechanism of action: Prokinetic drugs | block dopamine in CTZ,cause CTZ to be desensitizied to impulses it receives from the GI tract, stimulates peristalsis in GI tract, enhancing emptying of the stomach contents |
Prokinetic drugs are also used for ? - Metoclopramide (Reglan) | GERD |