What are the as-needed (prn) medications for heartburn?

PRN Medications for Heartburn

For as-needed (PRN) relief of heartburn, antacids are the first-line treatment option due to their rapid onset of action and proven efficacy for immediate symptom relief. 1

First-Line PRN Options

Antacids

• Mechanism: Directly buffer gastric acid in the esophagus or stomach
• Examples: Calcium carbonate, aluminum hydroxide, magnesium hydroxide
• Onset: Within minutes
• Duration: 30-60 minutes
• Evidence: Proven efficacy for self-treatment of individual heartburn episodes 1
• Formulations: Tablets, liquid, chewable tablets, gum
• Note: Calcium carbonate gum formulations provide faster and more prolonged symptom relief compared to standard chewable antacids 2

Second-Line PRN Options

H2-Receptor Antagonists (H2RAs)

• Mechanism: Decrease acid secretion by inhibiting histamine-2 receptors on gastric parietal cells
• Examples: Famotidine, ranitidine, cimetidine, nizatidine
• Onset: Within 30-60 minutes
• Duration: 6-8 hours
• Evidence: Low-dose famotidine (10-20 mg) provides more effective and rapid relief than placebo for spontaneous heartburn episodes 1
• Caution: Tachyphylaxis (decreased effectiveness) can develop within 6 weeks of regular use 3

Algorithm for PRN Heartburn Management

1. For mild, infrequent heartburn:

   • Start with antacids (calcium carbonate, aluminum/magnesium hydroxide)
   • Take at onset of symptoms
   • May repeat dose after 1-2 hours if needed

2. For moderate or predictable heartburn:

   • H2RAs (famotidine 10-20 mg) taken 30-60 minutes before anticipated trigger
   • Can be combined with antacids for breakthrough symptoms

3. For nocturnal heartburn:

   • H2RAs are more effective than antacids due to longer duration of action
   • Take 30-60 minutes before bedtime

Clinical Pearls

• Antacids provide the most rapid relief but have shorter duration of action compared to H2RAs 1, 2
• H2RAs provide longer symptom control (6-8 hours) but have slower onset than antacids 3
• Calcium carbonate gum formulations may provide superior relief compared to traditional chewable antacids 2
• On-demand use of low-dose H2RAs (famotidine 10-20 mg) is effective for self-treatment of episodic heartburn 1
• For patients with frequent heartburn (≥2 times/week), scheduled medication rather than PRN therapy may be more appropriate

Common Pitfalls to Avoid

• Overreliance on antacids alone for frequent heartburn can lead to inadequate symptom control
• Regular, long-term use of H2RAs can lead to tachyphylaxis within 6 weeks 3
• Failure to address lifestyle factors that trigger heartburn (dietary choices, meal timing, position)
• Delayed treatment - PRN medications work best when taken at first sign of symptoms rather than waiting until symptoms are severe
• Not recognizing when PRN therapy is insufficient - persistent symptoms despite PRN medications may indicate need for scheduled therapy or further evaluation

For patients with persistent symptoms despite appropriate PRN therapy, scheduled use of proton pump inhibitors (PPIs) may be necessary, but these are not typically used in a PRN fashion due to their delayed onset of action.