Proton Pump Inhibitors and H2 Blockers
Key Points
- PPIs (omeprazole, pantoprazole) irreversibly block the H⁺/K⁺-ATPase proton pump — more potent, longer-lasting acid suppression.
- H2 blockers (famotidine) competitively block H2 receptors on parietal cells — suppress basal and nocturnal acid secretion.
- PPIs must be taken 30–60 minutes before breakfast (delayed-release tablets); swallow whole — do not crush or chew.
- Indications: GERD, peptic ulcer disease, erosive esophagitis, H. pylori treatment adjunct, stress ulcer prophylaxis.
- Long-term PPI use risks: hypomagnesemia, C. difficile infection, vitamin B12 malabsorption.
Mechanism Comparison
| Feature | H2 Blockers | Proton Pump Inhibitors (PPIs) |
|---|---|---|
| Target | H2 receptors on parietal cells | H⁺/K⁺-ATPase (proton pump) in parietal cells |
| Acid suppression | Suppresses basal + nocturnal acid | Blocks all basal and stimulated acid |
| Reversibility | Reversible competitive blockade | Irreversible enzyme inhibition |
| Potency | Less potent | More potent |
| Onset | Faster onset of action | May take several days for full effect |
Drug Examples
Proton Pump Inhibitors
| Drug | Key Administration Points |
|---|---|
| Omeprazole (Prilosec) | 20 mg once daily; take 30–60 min before breakfast; swallow whole |
| Pantoprazole (Protonix) | 40 mg once daily; delayed-release tablet taken whole; granules: mix in apple juice/applesauce only |
| Esomeprazole (Nexium) | 20–40 mg once daily; if capsule opened, mix pellets in applesauce — do NOT chew |
| Lansoprazole (Prevacid) | 15 mg once daily; take 30 min before meal; acid symptom relief in ~1 week |
H2 Receptor Antagonists
| Drug | Key Administration Points |
|---|---|
| Famotidine (Pepcid) | 20 mg twice daily; available oral and IV; take 10–60 min before meals for heartburn |
| Cimetidine (Tagamet HB) | 400 mg 4×/day; IV: infuse over 15–20 min (never rapid bolus — arrhythmia/hypotension risk) |
| Nizatidine (Axid) | 150 mg twice daily; significantly reduces nocturnal acid for 12 hours |
Note: Ranitidine was recalled and is no longer available.
Indications
- GERD (gastroesophageal reflux disease) — primary indication
- Peptic ulcer disease (gastric and duodenal ulcers)
- Erosive esophagitis — healing and prevention
- H. pylori eradication — PPIs used as adjunct to antibiotic triple therapy
- Stress ulcer prophylaxis — in ICU patients, mechanically ventilated patients
- NSAID-induced gastric ulcer prevention (omeprazole)
- Zollinger-Ellison syndrome — hypersecretory states
- Perioperative aspiration prophylaxis — famotidine
Adverse Effects and Nursing Considerations
Short-Term Effects (Both Classes)
- Headache, dizziness, nausea, vomiting, diarrhea, abdominal pain
Long-Term PPI Risks (>8 weeks)
- Hypomagnesemia — monitor magnesium with prolonged use
- C. difficile infection risk — reduced gastric acid allows pathogen survival
- Vitamin B12 malabsorption — gastric acid required for B12 absorption
- Osteoporosis risk — calcium absorption impaired
- Possible cognitive-risk association — some cohort data suggest higher dementia risk with cumulative use; interpret cautiously and reassess necessity of prolonged therapy.
Cimetidine-Specific (H2 blocker)
- Drug interactions: warfarin, phenytoin, theophylline — cimetidine inhibits CYP enzymes
- IV rapid bolus → cardiac arrhythmias and hypotension — always infuse over 15–20 minutes
Nursing Interventions
- Administer oral PPIs 30–60 minutes before meals (activates in an acidic, stimulated environment)
- Never crush, chew, or break delayed-release/enteric-coated PPI formulations
- Pantoprazole granules: mix only in apple juice or applesauce; follow with sips of water
- Monitor GI symptoms: weight, nausea, abdominal pain, bowel habits
- Patient education: avoid alcohol, NSAIDs, spicy foods; complete full course even if symptoms resolve
- Antacids may be taken short-term while PPIs are reaching full effect (takes several days)
PPI Administration Timing
PPIs must be taken 30–60 minutes before the first meal of the day — they are activated by the meal-stimulated proton pump. Taking them with food or after eating significantly reduces efficacy.
Related Concepts
- digestive-system — Normal gastric acid secretion physiology and mucosal protection.
- cholecystitis — Peptic ulcer disease in differential for upper abdominal pain.
- proton-pump-inhibitors — Mucosal protective agents (sucralfate, misoprostol) used alongside acid suppression.
- diarrhea-assessment-and-management — C. difficile as a PPI-associated complication.
- nsaids — NSAIDs are a leading cause of peptic ulcer disease requiring PPI prophylaxis.
Self-Check
- A patient is prescribed omeprazole 20 mg daily for GERD. When should the nurse instruct the patient to take this medication?
- What is the key difference in mechanism between PPIs and H2 blockers?
- A patient receiving IV cimetidine develops sudden bradycardia. What administration error may have occurred?