Omeprazole vs. Famotidine: Effectiveness and Side Effects

A man is suffering from abdominal pain, stomach cramps and constipation.

Both Famotidine (Pepcid) and Omeprazole (Prilosec) are common medications used to treat gastroesophageal reflux disease (GERD) and “acid reflux.” Both medications are extremely effective at helping to assist with both GERD and acid reflux. However, there are some key differences between the two medications. Differences include side effects, effectiveness, and price.

Key Takeaways

Both Famotidine (Pepcid) and Omeprazole (Prilosec) are extremely effective at treating gastrointestinal issues. However, there are some differences. For example, Prilosec is in a class of drugs called “PPIs,” while Pepcid is considered an H2 blocker.
The prices of both medications are generally very similar, especially after coverage with most insurers. However, since both of these options are considered “over-the-counter” medications, most patients opt to purchase these medications out-of-pocket.
A clinical trial performed in 2005 compared the effectiveness of both drugs treating non-erosive gastro-oesophageal reflux disease (GERD) in 98 Japanese patients. These patients were randomly assigned to receive one of the drugs (famotidine or omeprazole). The results of the study showed that Omeprazole provided better symptom relief overall, especially in H. pylori-negative patients. However, both drugs significantly improved health-related quality of life for those suffering gastrointestinal issues.

Famotidine (Pepcid) Dosage, Side Effects, and Use

Based on the label provided by the FDA, Pepcid (Famotidine) can be broken down into the following key parts:

Category	Details
Initial U.S. Approval	1986
Indications and Usage	In adults and pediatric patients ≥40 kg: treatment of active duodenal ulcer, active gastric ulcer, symptomatic non-erosive GERD, erosive esophagitis due to GERD. In adults: treatment of pathological hypersecretory conditions, reduction of risk of DU recurrence.
Active Duodenal Ulcer Treatment	40 mg once daily or 20 mg twice daily.
Active Gastric Ulcer Treatment	40 mg once daily.
GERD Treatment	20 mg twice daily.
Erosive Esophagitis Treatment	20 mg twice daily or 40 mg twice daily.
Pathological Hypersecretory Conditions	20 mg every 6 hours, adjust to patient needs, max 160 mg every 6 hours.
Risk Reduction of DU Recurrence	20 mg once daily.
Administration	Take once daily before bedtime or twice daily in the morning and before bedtime, with or without food.
Dosage Forms and Strengths	Tablets: 20 mg, 40 mg.
Contraindications	History of serious hypersensitivity reactions to famotidine or other H2 receptor antagonists.
Warnings and Precautions	CNS adverse reactions in elderly and renal impairment patients; risk of GI malignancy despite absence of symptoms; evaluate prior to therapy.
Adverse Reactions	Common: headache, dizziness, constipation, diarrhea.
Drug Interactions	Avoid taking any other drugs dependent on gastric pH for absorption, tizanidine (CYP1A2 substrate).
Use in Specific Populations	Geriatric: use lowest effective dose and monitor renal function. Renal Impairment: reduce dosage due to CNS adverse reactions and QT prolongation risks.

Prilosec (Omeprazole) Dosage, Side Effects, and Use

Based on the label provided by the FDA, Prilosec (Omeprazole) can be broken down into the following key parts:

Category	Details
Initial U.S. Approval	1989
Indications and Usage	Treatment of duodenal ulcer, gastric ulcer, GERD, maintenance of healing of erosive esophagitis. Not established for pediatric patients <1 year.
Duodenal Ulcer Treatment	20 mg once daily for 4 weeks. May require an additional 4 weeks of treatment.
H. pylori Eradication Treatment	Triple Therapy: 20 mg Omeprazole, 1000 mg Amoxicillin, 500 mg Clarithromycin twice daily for 10 days. Dual Therapy: 40 mg Omeprazole once daily, 500 mg Clarithromycin three times daily for 14 days.
Gastric Ulcer Treatment	40 mg once daily for 4 to 8 weeks.
GERD Treatment	20 mg once daily for 4 to 8 weeks.
Maintenance of Erosive Esophagitis	20 mg once daily.
Hypersecretory Condition Treatment	60 mg (varies) once daily.
Pediatric Patients (1-16 years)	GERD and Maintenance of Erosive Esophagitis: 5 mg (<10 kg), 10 mg (10-20 kg), 20 mg (>20 kg) once daily.
Dosage Forms and Strengths	Capsules: 10 mg, 20 mg, 40 mg; Oral Suspension: 2.5 mg, 10 mg.
Contraindications	Hypersensitivity to components, substituted benzimidazoles (e.g., angioedema, anaphylaxis).
Warnings and Precautions	Possible gastric malignancy, atrophic gastritis, Clostridium difficile-associated diarrhea, bone fractures, diminished clopidogrel activity, hypomagnesemia, avoid with St. John's Wort or rifampin, diagnostic interactions.
Adverse Reactions	Adults: headache, abdominal pain, nausea, diarrhea, vomiting, flatulence. Pediatrics: similar to adults, with additional respiratory events and fever.
Drug Interactions	Atazanavir, nelfinavir (reduced levels); saquinavir (increased levels); effects drugs with gastric pH-dependent bioavailability; monitor with digoxin, warfarin, CYP 2C19/3A4 inhibitors, tacrolimus, methotrexate.
Use in Specific Populations	Consider dose reduction in patients with hepatic impairment, especially for maintenance of erosive esophagitis.

PPI Medications and H2 Blockers

Both Omeprazole and Famotidine are in a class of over-the-counter drugs. One of the medications belongs in a class of Proton Pump Inhibitors (PPIs) while another belongs in a class of H2 Blockers (H2-receptor antagonists). Making them effective at treating issues like Gastroesophageal Reflux Disease (GERD), peptic ulcer disease, zollinger-ellison syndrome, and erosive esophagitis.

Here is a breakdown of the key differences in PPIs and H2 blockers.

Proton Pump Inhibitors (PPIs)

Omeprazole is in a class of Proton Pump Inhibitors (PPIs). These PPIs are a class of medications that work by directly blocking the proton pump in a patient's stomach lining, which is directly responsible for secreting the gastric acid in the stomach. By inhibiting this pump, PPIs reduce the overall production of stomach acid.

This makes them highly effective for treating conditions related to excess stomach acid, such as:

Gastroesophageal Reflux Disease (GERD)
Peptic Ulcer Disease
Zollinger-Ellison Syndrome
Erosive Esophagitis

PPIs are often prescribed for both short-term and long-term treatment of these types of conditions due to their potent acid-suppressing abilities.

H2 Blockers (H2-Receptor Antagonists)

Famotidine belongs to a class of drugs known as H2 blockers or H2-receptor antagonists. These medications work by blocking histamine H2 receptors in the stomach lining, which play a role in signaling the production of gastric acid. By inhibiting these receptors, H2 blockers reduce the production of stomach acid.

They are used to treat conditions such as:

Gastroesophageal Reflux Disease (GERD)
Peptic Ulcer Disease
Gastric Ulcers
Hypersecretory Conditions

H2 blockers are generally effective in the short term, but they may be less effective than PPIs for long-term treatment due to the body developing tolerance, which can lead to a reduced response over time.

Feature	Omeprazole (PPI)	Famotidine (H2 Blocker)
Mechanism of Action	Inhibits the proton pump in stomach lining	Blocks H2 receptors in stomach lining
Effectiveness	Highly effective, especially for long-term use	Effective, but may develop tolerance over time
Side Effects	Potential for more gastrointestinal side effects	Fewer side effects, but can include headaches and dizziness
Long-term Risks	Potential for nutrient deficiencies, kidney issues, and infections	Generally considered safer for long-term use

Omeprazole (Pepcid) and Famotidine (Prilosec) Comparison Overview

Here is a general overview of the similarities and differences between the two medications:

Medication	Dosage	Retail Price	Insurance Coverage	Medicare Copay	Common Side Effects
Omeprazole (Pepcid)	20 mg capsules (30 qty)	~$100 per supply	Typically covered by insurance	$0–$19	Headache, stomach pain, nausea, vomiting, constipation, diarrhea, dizziness, fatigue, gas
Famotidine (Prilosec)	20 mg tablets (60 qty)	~$14.93 (6 tablets)	Typically covered by insurance	$0–$21	Headache, dizziness, constipation, diarrhea, nausea, vomiting, muscle pain, decreased libido, dry mouth, fatigue

Omeprazole is generally a little more expensive than Famotidine but is often covered by insurance and Medicare. Depending on your coverage, this can greatly reduce the out-of-pocket cost. For example, some discounts are available at online retailers that can bring down the total out-of-pocket cost to only around $2.

Famotidine is cheaper, with retail prices for a standard supply being around $14.93, and similar discount options bringing the cost down to about $3 at some retailers.

Both medications are generally covered by insurance and Medicare, making them accessible for most patients. The copay amounts vary slightly, with omeprazole generally being a bit cheaper on Medicare.

The side effects for both medications are somewhat similar, with omeprazole having a slightly broader range of potential gastrointestinal side effects. Famotidine is noted to have fewer long-term risks compared to omeprazole.

Effectiveness of Omeprazole (Pepcid) and Famotidine (Prilosec)

A clinical trial performed in 2005 compared the effectiveness of famotidine and omeprazole in treating non-erosive gastro-oesophageal reflux disease (GERD) in 98 Japanese patients, where Helicobacter pylori (H. pylori) infection is more prevalent. These patients were randomly assigned to receive either famotidine or omeprazole. Omeprazole provided better symptom relief overall, especially in H. pylori-negative patients. Both drugs improved health-related quality of life.

The “H. pylori relief rate” in the table below refers to the percentage of patients achieving complete symptom relief based on their H. pylori infection status. In this study, H. pylori-positive patients had better relief rates with famotidine, while omeprazole was effective regardless of H. pylori status. A patient with a positive test result for Helicobacter pylori (H. pylori) indicates an infection with the bacteria that can cause stomach ulcers and peptic ulcer disease. The importance of testing patients with H. pylori would indicate a stronger need for relief.

Aspect	Famotidine	Omeprazole
Patient Group	48	50
Dosage	20 mg b.d.	Once daily
Complete Relief Rate	48% (23 patients)	56% (28 patients)
H. pylori-Negative Relief Rate	35%	Significantly improved regardless
H. pylori-Positive Relief Rate	64%	Significantly improved regardless
Health-Related Quality of Life	Improved most scales	Improved most scales
Reflux Score Improvement	Significant in H. pylori-positive	Significant regardless of H. pylori
Conclusion	Less effective in H. pylori-negative, similar efficacy in H. pylori-positive	More effective in H. pylori-negative, similar efficacy in H. pylori-positive

Common Questions

Questions about both medications:

Can I take omeprazole and famotidine together?

There are no current and distinguished negative drug interactions between omeprazole and famotidine. Meaning that in some cases, omeprazole and famotidine can be used together. While PPIs are usually sufficient to treat digestive disorders like GERD, some people may need extra treatment to manage and control acid production at night (H2 blockers).

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Sources

Kinoshita, Y., Adachi, K., Hongo, M., Haruma, K., & Kusano, M. (2005). Comparison of famotidine and omeprazole for non-erosive gastro-oesophageal reflux disease in Japanese patients: A randomized, double-blind, multicentre study. Alimentary Pharmacology & Therapeutics, 21(3), 277-285. https://pubmed.ncbi.nlm.nih.gov/15943841/
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U.S. Food and Drug Administration. (2018). Pepcid (famotidine) labeling. https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/019462s039lbl.pdf
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