Nausea and Vomiting

Table Of Contents
1 Types of Emetics
2 Antihistamines
3 Muscarinic Receptor Antagonists
4 D2 Receptor Antagonisits
5 5HT3 Receptor Antagonists
6 N&V of Pregnancy (NVP)

Types of Emetics

  • H1 Receptor Antagonists
  • Muscarinic Receptor Antagonists
  • D2 Receptor Antagonists
  • 5HT3 Receptor Antagonists
  • Substance P (NK1) Antagonists

Antihistamines

  • MOA: H1 Receptor Antagonists
  • Types:
    • Dimenhydrinate (Dramamine)
    • Diphenhydramine (Benadryl)
    • Meclizine (Antivert)
    • Doxylamine (Unisom)
      • Used for all types of vomiting including motion sickness
    • Promethazine (Phenergan)

      • all types of vomiting including severe morning sickness in pregnancy (only if absolutely essential), prevention of motion sickness

    • Cinnarizine (Cizinate)
      • motion sickness,
      • vestibular disorders (Meniere’s)
    • Cyclizine (Valoid)
      • Used for all types of vomiting including motion sickness
    • Buclizine
      • motion sickness,
      • radio/chemo-induced NV

Muscarinic Receptor Antagonists

  • MOA: M receptors, blocks impulses from the CTZ to the vomiting centre (act directly on the VC)
  • Hyoscine (Scopolamine)

D2 Receptor Antagonisits

  • Types:
    • Prochlorperazine (Compazine)
    • Metoclopramide (Reglan)
    • Domperidone (Motilium)
    • Droperidol (Inapsine)

5HT3 Receptor Antagonists

  • Ondansetron (Zofran)
  • Granisetron (Sustol)
  • Palonosetron (Aloxi)

N&V of Pregnancy (NVP)

  • Etiology:
    • 70-80% experience this in their 1st trimester 
    • Severe N/V = hyperemesis gravidarum (HG)
  • Non-pharmacologic therapies:
    • Prenatal multivitamin for 1 month before planned conception.
    • Eating small frequent meals.
    • Eat crackers before getting out of bed. 
    • Get up slow. 
  • Pharmacologic:
    • Pyridoxine (Vit B6) 10-25 mg Q8h with OR without Doxylamine 10-12.5mg Q8h.
    • sucrose/phosphoric acid
    • dicyclomine/ doxylamine succinate/ pyridoxine