Pharmacology & Anesthesia: Anti-Reflux Medication

Antacids

Principals

  • Mechanism: Neutralize Gastric Acid to Provide Rapid Relief
  • Does Not Prevent Acid Build Up
  • Onset: Minutes
  • Duration:
    • Empty Stomach: 20-40 Minutes
    • Full Stomach: 2-3 Hours

Drugs

  • Tums (Calcium Carbonate)
  • Rolaids (Calcium Carbonate & Magnesium Hydroxide)
  • Maalox (Aluminum Hydroxide, Magnesium Hydroxide & Simethicone)
  • Mylanta (Aluminum Hydroxide, Magnesium Hydroxide & Simethicone)
  • Alka-Seltzer (Aspirin, Sodium Bicarbonate & Anhydrous Citric Acid)

GI Cocktail

  • Active Ingredients:
    • Antacid
    • Viscous Lidocaine – Pain Relief
    • Anticholinergic Agent (Donnatal) – Relieve Nausea & Cramping
  • Benefit Over Antacids Alone is Questioned & Generally No Longer Used

Complications

  • Depend on Active Ingredients
  • Calcium Carbonate – Hypercalcemia, Alkalosis & Renal Injury
  • Magnesium Hydroxide – Diarrhea & Hypermagnesemia
  • Aluminum Hydroxide – Neurotoxicity & Hypophosphatemia

Acid Blockers

Proton Pump Inhibitors (PPI)

  • Mechanism: Irreversibly Blocks H/K ATPase Pump
  • Agents:
    • Omeprazole (Prilosec)
    • Pantoprazole (Protonix)
    • Lansoprazole (Prevacid)
    • Esomeprazole (NexIUM)
    • Dexlansoprazole (Dexilant)
  • Onset: 3-4 Days to Reach Peak Effect
  • Duration: 1-3 Days
  • Side Effects:
    • Increased Risk of Clostridioides difficile Infection
    • Hypomagnesemia

Histamine-2 (H2) Receptor Blocker

  • Mechanism: Blocks H2 Receptors on Parietal Cells
  • Agents:
    • Famotidine (Pepcid)
    • Cimetidine
    • Nizatidine
    • Ranitidine (Zantac) – Recalled Due to High Levels of N-Nitrosodimethylamine (NMDA), a Probable Human Carcinogen
  • Onset: 30-60 Minutes
  • Duration: 8-12 Hours
  • Side Effects:
    • Gynecomastia
    • Impotence
    • Confusion & Agitation

Comparison

  • Proton Pump Inhibitors:
    • Stronger Acid Suppression
    • Faster Acid Reduction & Symptom Control
    • Higher Ulcer Healing Rates
    • Lower Risk of Upper GI Bleeding
  • H2 Receptor Blockers:
    • Reduce Acid Release in the Evening
    • Patients May Develop a Tolerance
  • Same Risk of Pneumonia & Mortality
  • Oral & IV Effects are Equivalent