Gastric Acid Neutralization: Antacids

Chapter Overview

• Antacids are the most commonly used non-prescription drugs.

Mechanism of Action

• Neutralization of Stomach Acid: Antacids neutralize existing stomach acid; they do not prevent its overproduction.
• Stimulation of Secretions:
  • Mucus: Serves as a protective barrier against hydrochloric acid and digestive enzymes.
  • Prostaglandin: Prevents histamine binding on parietal cells.
  • Bicarbonate: Acts as a buffer for hydrochloric acid.

Therapeutic Effects

• Relief of symptoms related to hyperacidity:
  • Heartburn
  • Gastritis
  • Peptic Ulcer Disease (PUD)

Precautions

• Antacids may inhibit the absorption or activity of other drugs if taken concurrently. Timing of administration with other medications is critical.

Contraindications

• Gastrointestinal (GI) obstruction.
• Possible renal failure.

Side and Adverse Effects

• Magnesium Preparations:
  • Diarrhea
  • Increased magnesium levels, especially in renal failure.
• Aluminum and Calcium Preparations:
  • Constipation
  • Kidney stones (particularly with calcium preparations, as stones are often calcium-based).
  • Rebound hyperacidity if used long-term and then abruptly stopped.
• Metabolic Alkalosis: Due to over-neutralization of stomach acids.

Nursing Actions

• Assess therapeutic and side effects.
• Follow-up evaluation.
• Educate patients on use and need for follow-up evaluations.

Drug Prototypes

• Magnesium Hydroxide
• Aluminum Hydroxide
• Calcium Carbonate

Key Points to Remember

• Focus on understanding the effects of magnesium, aluminum, and calcium preparations.
• Be cautious of drug interactions and side effects.
• Remember the importance of secretion stimulation in the mechanism of action.