The Differences Between Famotidine and Omeprazole
Clubfoto / Getty Images
OmeprazoleMedically reviewed by Erika Prouty, PharmD
Famotidine (brand name Pepcid) and omeprazole (brand name Prilosec) are popular treatment options for heartburn.
Famotidine is a histamine-2 receptor blocker that treats gastroesophageal reflux disease (GERD). It also treats or prevents the following:
Other hypersecretory conditions (conditions that involve increased stomach acid production)
Omeprazole is a proton pump inhibitor (PPI) used to treat similar conditions in addition to Helicobacter pylori (H. pylori) infections.
The National Institutes of Health estimates that more than 60 million Americans experience heartburn at least once a month. About 15 million experience heartburn symptoms daily.
Common heartburn symptoms include the following:
A feeling of warmth or burning in your throat
Pain or burning sensation in the middle of your chest
A foul taste in your mouth
These symptoms are the result of stomach acid backing up into your esophagus (food tube).
Keep reading to learn more about how omeprazole and famotidine compare to help you determine if one of these medications might be helpful for you.
What Is Famotidine?
Famotidine is a generic medication that belongs to a drug class called histamine type-2 receptor antagonist (H2RA), also known as H2 blockers.
Famotidine is available in over-the-counter (OTC) and prescription strengths. Brand-name versions include the following:
Pepcid
Pepcid AC
Zantac 360
The Food and Drug Administration (FDA) approved OTC versions of famotidine for different indications than the prescription versions.
OTC famotidine (such as Pepcid AC) is used to prevent and treat heartburn in adults and children 12 years and older.
The prescription version of famotidine is FDA-approved to treat the following in adults and some children:
The FDA also approved prescription famotidine use in adults for the following:
Preventing gastrointestinal ulcers
Treating conditions that cause excess stomach acid (e.g., in Zollinger-Ellison syndrome and multiple endocrine neoplasia syndrome)
How Does Famotidine Work?
You may have heard of histamine and the role it plays in allergies. Histamine also stimulates stomach acid production in the body. Some people produce too much stomach acid at times.
GERD and heartburn symptoms occur when the stomach acid backs up into your esophagus, causing irritation and discomfort.
Famotidine blocks a specific type of histamine receptor to relieve GERD symptoms. By blocking the stimulation from histamine, famotidine decreases acid in your stomach. This results in less irritation.
Taking famotidine 15 to 60 minutes before eating or drinking can help prevent or lessen heartburn symptoms.
Famotidine starts working within one hour, and its effects last about 12 hours.
What Is Omeprazole?
Omeprazole is a generic medication that belongs to a class of drugs called proton pump inhibitors (PPIs). Omeprazole is available in prescription and nonprescription (OTC) strengths.
The FDA has approved OTC omeprazole for different indications than the prescription version. OTC omeprazole (Prilosec OTC) treats frequent heartburn in people age 18 years and older who have heartburn symptoms at least two days a week.
Unlike famotidine, omeprazole is not meant to provide quick relief from heartburn and, initially, can take a few days to start working.
OTC omeprazole is typically taken once daily for 14 days. You shouldn’t take it for more than 14 days unless advised by a healthcare provider.
The prescription version of omeprazole is FDA-approved to treat damage from GERD in adults and children older than 1 month of age.
Prescription omeprazole is also approved to treat the following in adults:
Other hypersecretory conditions (too much stomach acid), like Zollinger-Ellison syndrome
Omeprazole may be prescribed for short-term or long-term use, depending on the condition.
How Does Omeprazole Work?
As a proton pump inhibitor, omeprazole lowers the amount of acid in your stomach but does so in a different way than famotidine.
Omeprazole works by inhibiting the pumping of gastric acid and blocking the final step in acid production.
Omeprazole is not an antacid, and it does not provide instant relief from heartburn symptoms. It can take one to four days of treatment before omeprazole reaches its full effect.
However, some people will notice some relief of heartburn symptoms within the first 24 hours. It usually keeps working to decrease stomach acid production for about a day.
How Do the Dosages Compare for Famotidine vs. Omeprazole?
Famotidine and omeprazole have different recommended dosages.
The table below summarizes the available dosage forms, strengths, and typical dosages for adults and children.
Your healthcare provider may adjust or reduce your dosage if you have certain health conditions, kidney impairment, or if you take other medications.
Be sure to take the dosage your provider recommends.
| Famotidine | Omeprazole |
Dosage forms and strengths available: | OTC: ● Oral tablet: 10 milligrams (mg), 20 mg ● Chewable tablet: 10 mg, 20 mg Prescription: ● Oral tablet: 20 mg, 40 mg ● Oral suspension: 40 mg per 5 milliliters (mL) ● Injection: 0.4 mg per milliliter (mg/mL), 10 mg/mL | OTC: ● Oral tablet: 20 mg ● Oral capsule: 20 mg ● Orally disintegrating tablet (ODT): 20 mg Prescription: ● Oral capsule: 10 mg, 20 mg, 40 mg ● Granules for oral suspension: 2.5 mg, 10 mg |
Adult dosage (varies with condition): | Heartburn: ● 10–20 mg once or twice daily as needed GERD: ● Erosive esophagitis (tissue-lining damage): 20–40 mg by mouth twice daily for up to 12 weeks ● Non-erosive: 20 mg by mouth twice daily for up to 6 weeks Ulcers: ● Active ulcer: 40 mg by mouth at bedtime for 4–8 weeks ● Maintenance: 20 mg by mouth at bedtime Hypersecretory conditions: ● 20–60 mg by mouth every 6 hours | Heartburn: ● 20 mg once daily for 14 days GERD: ● Erosive esophagitis: 20 mg by mouth once daily for 4–12 weeks ● Non-erosive (no tissue-lining damage): 20 mg by mouth once daily for 4–8 weeks Ulcers: ● Active ulcer: 20-40 mg by mouth once daily for 4–8 weeks ● Maintenance: 20 mg by mouth once daily Hypersecretory conditions: ● 60 mg by mouth once daily H. pylori infection: ● 20 mg by mouth twice daily for 10–14 days as part of a multidrug regimen |
Famotidine and omeprazole can also be prescribed to children. The dosages vary depending on the child’s age, weight, and condition. Your child’s healthcare provider will recommend or prescribe the dosage that suits your child’s needs.
Famotidine is approved for the following uses in children:
Relieving and preventing heartburn (ages 12 years and older)
Treating peptic ulcer disease (ages 1 year and older)
GERD in children of any age, including infants
Omeprazole is approved for treating the following conditions in children:
GERD: Non-erosive (ages one year and older)
GERD: Erosive esophagitis (ages one month and older)
Side Effects & Precautions
This section summarizes the common, serious, and potential long-term side effects of famotidine and omeprazole.
These lists are not all-inclusive; other side effects may occur.
Common side effects of famotidine include but are not limited to the following:
Common side effects of omeprazole include but are not limited to the following:
Flatulence
Respiratory symptoms, such as cough (in children)
Fever (in children)
Rarely, serious or long-term side effects of famotidine have been reported, such as the following:
Muscle or joint pain
Mental reactions, such as confusion, delirium, or hallucinations in elderly adults and people with kidney impairment
Arrhythmia (irregular heartbeat)
Rarely, serious or long-term side effects of omeprazole have been reported, such as the following:
Acute interstitial nephritis, a kidney problem
Increased risk of Clostridium difficile (C. diff)–associated diarrhea
Increased risk of esophageal cancer
Low magnesium levels with long-term treatment (three months or longer)
Increased risk of bone fractures with long-term treatment (longer than a year)
Fundic gland polyps with long-term treatment (longer than a year)
Vitamin B12 deficiency with long-term treatment (longer than a year)
If you take omeprazole on a long-term basis, your healthcare provider may recommend specific dietary supplements, such as vitamin B12, magnesium, or other minerals.
Before taking OTC famotidine or omeprazole, be sure to check the label for any precautions or warnings that may apply to you.
Check with your healthcare provider or pharmacist before taking these medications if you have any health conditions, take other medications or supplements, or if you are pregnant or breastfeeding.
Interactions for Famotidine vs. Omeprazole
Drug interactions are possible with famotidine and omeprazole. This section describes some of the most important interactions to be aware of, but others may occur.
Examples of interactions with famotidine include the following:
Zanaflex (tizanidine)
Risk of reduced effectiveness if taken with drugs or supplements that depend on stomach acid to be absorbed, such as iron, Tarceva (erlotinib), Sprycel (dasatinib), Cellcept (mycophenolate mofetil), and ketoconazole.
Examples of interactions with omeprazole include the following:
Specific human immunodeficiency virus (HIV) medications, such as rilpivirine
Saint-John’s-wort, an herb also known as Hypericum perforatum
Blood thinners like Jantoven (warfarin) and Plavix (clopidogrel)
Celexa (citalopram)
Rifampin
Risk of reduced effectiveness if taken with drugs or supplements that depend on stomach acid to be absorbed, such as iron, Tarceva (erlotinib), Sprycel (dasatinib), Cellcept (mycophenolate mofetil), and ketoconazole
Before starting famotidine or omeprazole, tell your healthcare provider about all of the OTC drugs, supplements, and medications you take. Your provider can ensure they are safe to take together.
What Are Other Ways To Help Manage GERD?
Some people can manage GERD symptoms by making lifestyle changes.
Your healthcare provider may recommend the following tips that can help:
Eat smaller meals
Eat at least two to three hours before lying down
Attempt weight loss if you're overweight or obese
Avoid foods and drinks known to trigger symptoms
Foods and drinks that commonly cause or worsen acid reflux symptoms include the following:
Fried foods
Pizza
Chili powder
Peppers
Chocolate
Cheeses
Acidic foods, like tomatoes and citrus
The following foods may help prevent acid reflux:
Whole grains
Vegetables
Bananas
Nuts
Raising the head of your bed may significantly help nighttime GERD symptoms.
Breathing exercises have been studied for their use in GERD with reduced symptoms.
Probiotics may benefit GERD, but more research is needed.
For personalized nutrition guidance, consider seeing a registered dietitian (RD) or registered dietitian nutritionist (RDN).
Sometimes, lifestyle changes aren’t enough to control acid reflux symptoms. For best results, continue to follow lifestyle and dietary changes while taking medications for GERD.
Summary
Famotidine and omeprazole are used to treat similar conditions but work in different ways to reduce stomach acid.
These drugs are also similar in that they are available both in OTC and prescription strengths.
Both medications can cause side effects and should not be continued for long-term treatment without the supervision of a healthcare provider.
Speak with your healthcare provider if you have questions about whether famotidine or omeprazole may be right for you.
Frequently Asked Questions
Can you take omeprazole and famotidine together?
Yes. While most people find relief with just one medication, healthcare providers sometimes recommend taking both omeprazole and famotidine for severe symptoms. It is safe to use both since they work differently in the body. For example, your provider may suggest taking omeprazole upon waking in the morning and famotidine before your evening meal. Taking both can provide an additive effect to reduce reflux symptoms.
Which is safer, omeprazole or famotidine?
Both omeprazole and famotidine are generally safe medications with short-term use as long as you follow the prescribed instructions. In general, famotidine tends to cause fewer short-term side effects, such as nausea, vomiting, and stomach upset.
Both omeprazole and famotidine are associated with long-term side effects, some of which can be serious. Taking famotidine long term can result in muscle or joint pain, heart palpitations, depression, anxiety, seizures, and liver damage. Taking omeprazole long term (more than a year) raises the risk of esophageal cancer, bone fractures, infections, and vitamin B12 deficiency. Talk to a healthcare provider to weigh the possible risks and benefits of either medicine.
What is the difference between over-the-counter omeprazole (Prilosec OTC) and prescription omeprazole?
They have different indications (specific uses), as approved by the FDA.
Over-the-counter (OTC) omeprazole is indicated to relieve frequent heartburn occurring two or more days a week in adults (ages 18 years and older). It comes in a 20 mg strength that’s typically taken once a day for 14 days.
Prescription omeprazole is FDA-approved to treat GERD in adults and children, including infants older than 1 month of age.
Additionally, prescription-strength omeprazole is indicated to treat ulcers, H. pylori infections, and other conditions in which the stomach produces excess acid. Prescription omeprazole doesn’t have a 14-day limit and comes in various strengths ranging from 2.5 mg to 40 mg.
