Pharmacology & Anesthesia: Antiemetics

Serotonin (5-HT3) Antagonists

• Drugs:
  • Ondansetron (Zofran) – 4-8 mg PO/IV Q8hr PRN
  • Granisetron (Sustol) – 2 mg PO or 10 mcg/kg IV Once Before Chemotherapy
  • Dolasetron (Anzemet) – 100 mg PO Once Before Chemotherapy
  • Palonosetron (Axoli) – 0.25 mg IV
    • Second Generation
    • No QT Prolongation & Longer Half-Life
• No Sedative or Extrapyramidal Effects
• Major Side Effects:
  • Most Common: Headache & Constipation
  • QT Prolongation
  • QRS Widening
  • Hypersensitivity – Rare

Dopamine Antagonists

• Drugs:
  • Phenothiazines:
    • Prochlorperazine (Compazine) – 5-10 mg IV Q4hr PRN
    • Promethazine (Phenergan) – 12.5-25 mg PO Q4hr PRN
      • Avoid IV Use – Extravasation Can Cause Tissue Necrosis
    • Chlorpromazine (Thorazine) – Generally Not Used for Nausea/Vomiting
  • Butyrophenones:
    • Haloperidol (Haldol) – 2-3 mg IM/IV Q4hr PRN
    • Droperidol (Inapsine) – 0.626-1.25 mg IV Q4hr PRN
  • Metoclopramide (Reglan) – 10-25 mg IV Q4hr PRN
• Major Side Effects:
  • Sedation
  • Extrapyramidal Effects
  • QT Prolongation
  • Bradycardia & Hypotension
  • Seizure
  • Neuroleptic Malignant Syndrome
  • Agranulocytosis

Anticholinergic Agents

• Scopolamine (Transderm Scop) – Transdermal Patch, 1.5 mg Every 72 Hours
• Major Side Effects:
  • Sedation
  • Dry Mouth
  • Urinary Retention
  • Exacerbation of Narrow-Angle Glaucoma

Antihistamines

• Drugs:
  • Diphenhydramine (Benadryl) – 25 mg PO or 10-50 mg IV Q4-6hr PRN
  • Dimenhydrinate (Dramamine) – 50-100 mg PO/IV Q4-6hr PRN
  • Meclizine (Antivert) – 12.5-25 mg PO Q6-8hr PRN
  • Cyclizine (Marezine) – 50 mg IV Q8hr PRN
• Major Side Effects:
  • Sedation
  • Dry Mouth
  • Urinary Retention
  • Exacerbation of Narrow-Angle Glaucoma

Other Agents

• Aprepitant (Cinvanti/Emend)
  • Mechanism: NK-1 Receptor Antagonist
  • Good Second Line Choice for Chemotherapy-Induced Nausea
• Cannabinoids
• Glucocorticoids:
  • Dexamethasone
  • Methylprednisolone (Medrol)