Omeprazole vs. Famotidine
See how Omeprazole and Famotidine compare on approved uses, dosing, side effects, and cost.
Key Takeaways
Omeprazole is a proton pump inhibitor that blocks acid production for up to 24 hours, while famotidine is an H2 blocker that works within an hour but wears off after 8 to 12 hours.
Both drugs treat GERD, erosive esophagitis, and stomach or duodenal ulcers, but omeprazole is generally considered more effective for frequent or severe acid reflux.
Famotidine carries fewer labeled long-term risks, while extended omeprazole use is linked to bone fracture, vitamin B12 deficiency, and C. diff diarrhea.
Omeprazole vs. Famotidine Drug Summary
Omeprazole
Omeprazole is a proton pump inhibitor (PPI) used to treat GERD, erosive esophagitis, and stomach or duodenal ulcers by blocking the enzyme that produces stomach acid. It is typically taken once daily before breakfast and can take one to four days to reach full effect, but it suppresses acid for up to 24 hours.
Famotidine
Famotidine is a histamine H2-receptor antagonist used to treat GERD, erosive esophagitis, and duodenal or gastric ulcers by blocking histamine's signal to produce stomach acid. It starts working within about an hour and is usually taken once or twice daily, with each dose lasting 8 to 12 hours.
Omeprazole vs. Famotidine Side Effects
Omeprazole
Famotidine
Omeprazole vs. Famotidine Dosage
Omeprazole
Famotidine
| STAGE | DOSE | WHEN |
| Starting dose | 20 mg once daily | At the start |
| Maximum dose | 40 mg once daily | If needed |
| Dose changes | 1 increase | As tolerated |
| STAGE | DOSE | WHEN |
| Starting dose | 20 mg twice daily | Weeks 1-6 |
| Maximum dose | 40 mg once daily | Weeks 1-8 |
| Dose changes | 1 increase | As tolerated |
Omeprazole
| STAGE | DOSE | WHEN |
| Starting dose | 20 mg once daily | At the start |
| Maximum dose | 40 mg once daily | If needed |
| Dose changes | 1 increase | As tolerated |
Famotidine
| STAGE | DOSE | WHEN |
| Starting dose | 20 mg twice daily | Weeks 1-6 |
| Maximum dose | 40 mg once daily | Weeks 1-8 |
| Dose changes | 1 increase | As tolerated |
Omeprazole vs. Famotidine Indications
Omeprazole
Omeprazole is FDA-approved for short-term treatment of GERD, erosive esophagitis, and duodenal or gastric ulcers, plus long-term management of conditions that cause excess acid, such as Zollinger-Ellison syndrome. It is also combined with antibiotics to treat H. pylori infection linked to ulcers.
Gastroesophageal reflux disease (GERD)
Erosive esophagitis due to GERD
Duodenal ulcer and gastric ulcer
H. pylori eradication (with antibiotics)
Pathological hypersecretory conditions (e.g. Zollinger-Ellison syndrome)
Famotidine
Famotidine is FDA-approved for treating and maintaining healing of duodenal and gastric ulcers, GERD, and erosive esophagitis. It also treats pathological hypersecretory conditions such as Zollinger-Ellison syndrome, and a lower-dose version is sold over the counter for occasional heartburn.
Duodenal ulcer treatment and maintenance
Benign gastric ulcer
Gastroesophageal reflux disease (GERD)
Erosive esophagitis due to GERD
Pathological hypersecretory conditions (e.g. Zollinger-Ellison syndrome)
Omeprazole vs. Famotidine Pros and Cons
Omeprazole
Omeprazole provides stronger, longer-lasting acid suppression than famotidine, which makes it a common choice for frequent or erosive GERD. Its FDA label also carries specific warnings about long-term risks that build up with continued use.
Pros
Suppresses acid for up to 24 hours after each dose
Once-daily dosing works well for chronic, frequent symptoms
Generally more effective for erosive esophagitis and frequent GERD
Also treats H. pylori infection when combined with antibiotics
Cons
Takes 1 to 4 days to reach full effect, not ideal for acute symptoms
FDA label warns of long-term risks: bone fracture, B12 deficiency, C. diff diarrhea
Inhibits CYP2C19, raising risk of interactions with drugs like clopidogrel
Famotidine
Famotidine works faster than omeprazole and clears the body more quickly, so it's often chosen for occasional or milder heartburn. It carries no boxed warning and has a shorter list of long-term safety concerns, but its acid-blocking effect is weaker and shorter-lived.
Pros
Starts working within about an hour for faster relief
Fewer long-term safety concerns than PPIs like omeprazole
No CYP-mediated drug interactions like omeprazole
Flexible as-needed dosing for occasional symptoms
Cons
Weaker acid suppression than a PPI
Effects wear off after 8 to 12 hours, needing more frequent doses
Dose must be lowered in moderate to severe kidney impairment
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