Nausea & Vomiting

Question 1

Ondansetron

Answer 1

N/V
5 HT3 receptor antagonist
Therapeutic  
-*(primary)chemotherapy induced nausea and vomiting
-Postoperative and postradiation nausea and vomiting 
MOA
-selective 5-HT3 receptor antagonist 
Adverse Effects 
-Headache, dizziness, and constipation 
-Prolonged QT interval 
Drug interactions
-Other drugs alter clearance and half life

Question 2

Dexamethasone

Answer 2

N/V
Corticosteroids
Therapeutic
-Enhance efficacy of Serotonin 5-HT3 receptor antagonist 
MOA
-Bind Glucocorticoid Receptors
CLINICAL NOTE
-Standard regime for chemo induced nausea is Serotonin antagonist and corticosteroid

Question 3

Aprepitant

Answer 3

N/V
NK1 Receptor Antagonist•
Pharmacokinetics
-Oral, metabolized by CYP3A4 therefore may inhibit other drug metabolism
-induced CYP2CP, increases metabolism of warfarin.
Therapeutic
-prophylaxis in combo w/ standard regime for chemo induced nausea/vomiting. -Acute and delayed nausea and vomiting
Adverse effects
-Fatigue, dizziness, diarrhea
Drug interactions
-Decreases INR in patients taking warfarin therefore need to adjust dosage

Question 4

Prochlorperazine, Promethazine

Answer 4

N/V
Phenothiazines (Antipsychotic
Antiemetic)
Therapeutic
-“general purpose” anti-emetics, motion sickness (irradiation sickness, postoperative, drug induced)
MOA
-Preferentially blocks dopamine receptors
Prochlorperazine
•Dopamine Antagonist, antimetic inhibition dopamine and muscarinic receptors
Promethazine
•Dopamine Antagonist, antimetic inhibition of dopamine, muscuranic, and *histamine receptors.
Adverse effects
-constipation dry mouth, parkinsonism, blurred vision and sedation
Contraindications
-CNS depression

Question 5

Metoclopramide

Answer 5

N/V
Substituted Benzamides
Therapeutic
-prevention and treatmenet of emesis  
MOA
-Antimetic, dopamine antagonist
Adverse Effects
-Restlessness, insomnia, and anxiety. 
-Extrapyramidal effects (dystonias, akathisia, parkinsonian)
Contraindications 
-Stimulation of GI motility is dangerous

Question 6

Scopalamine

Answer 6

N/V
M1 Receptor Antagonist
Therapeutic
-Prevention of nausea and vomiting recovery from anesthesia and surgery. 
-*Motion Sickness
MOA
-antimuscarinic antagonist
Adverse Effects
-Mydriasis, dry mouth, constipation, blurry vision 
Contraindication
-Angle-closure glaucoma