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Prilosec vs. Pepcid OTC: Which is right for you?

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UsesSide effectsTimingsStrengthsCan you take both?Prescription medsSummary
Prilosec and Pepcid are over-the-counter (OTC) versions of omeprazole and famotidine, respectively. People often use them to help relieve acid reflux and related conditions, but you may prefer one over the other depending on your symptoms.
Medically reviewed by Alisha D. Sellers, BS Pharmacy, PharmD
Written by Rashida Ruwa, RN
Updated on

Acid reflux is when stomach acid flows back into your food pipe (esophagus), causing a burning sensation in the chest, known as heartburn. Persistent acid reflux may lead to esophageal damage if untreated.

Chronic acid reflux may require prescription medications, but OTC options often also help.

Prilosec and Pepcid work by reducing the production of stomach acid, which in turn relieves symptoms of acid reflux.

Prilosec contains omeprazole, while Pepcid’s active ingredient is famotidine. You can purchase both active ingredients as generic medications. Omeprazole and famotidine are also available as prescription medications with higher potency.

Choosing the generic option can provide a more affordable alternative without compromising the effectiveness of the medication. 

Prilosec vs. Pepcid: Uses

Man in bed taking Prilosec or Pepcid for acid reflux at night
Photography by Shironosov/Getty Images

Prilosec and Pepcid reduce the production of stomach acid.

Omeprazole (Prilosec) belongs to the proton pump inhibitor (PPI) drug class, while famotidine (Pepcid) is an H2 blocker. Both of these drug classes treat acid reflux and related conditions like indigestion, stomach ulcers, and gastroesophageal reflux disease (GERD).

Prilosec is additionally approved to treat helicobacter pylori bacterial infections in the stomach.

Both Prilosec and Pepcid are generally safe for short-term use.

Omeprazole, like other PPIs, has been associated with some risks when used long term. Studies have shown that long-term PPI use may increase the risk of certain conditions, such as kidney disease, osteoporosis-related fractures, and vitamin B12 deficiency.

On the other hand, famotidine, like other H2 antagonists, is considered safer for long-term use.

Safety and effectiveness for long-term use may vary individually. Consider talking with a healthcare professional to determine which option is best for you.

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Prilosec vs. Pepcid: Side effects

Although Prilosec and Pepcid are generally well-tolerated, they may lead to side effects in some people. 

Commonly reported side effects of Prilosec include:

  • headaches
  • stomach pain
  • diarrhea
  • nausea and vomiting
  • gas (flatulence)

While possible side effects of Pepcid include:

  • constipation
  • fatigue
  • headaches
  • dizziness
  • diarrhea

These side effects are typically mild and temporary. However, it’s best to speak with a healthcare professional if you experience persistent or severe side effects.

Prilosec vs. Pepcid: How long they take to work

Prilosec takes longer to work compared to Pepcid. It may take 1–4 days to experience symptom relief after taking Prilosec.

If you need faster relief of occasional symptoms, Pepcid typically works within 15–30 minutes

To boost its effectiveness, healthcare professionals recommend taking Prilosec OTC in the morning on an empty stomach, as this may help reduce stomach acid production throughout the day. If you need to take Prilosec OTC twice daily, the second dose should be before dinner.

You can take Pepcid any time of the day or night, depending on when you experience symptoms. Some people find it beneficial to take it before meals or at bedtime to help manage acid-related issues during the night.

A healthcare professional can help you decide the most suitable timing for Prilosec or Pepcid, considering factors such as your symptoms, medical history, and whether you’re taking other medications.

Download the free Optum Perks Discount Card to save up to 80% on some prescription medications.

Prilosec vs. Pepcid: Strengths

Both omeprazole and famotidine are available in OTC and prescription potencies.

OTC omeprazole (Prilosec) is available in 20 milligrams (mg) only. The prescription version only comes as a generic medication and is available in strengths of 10 mg, 20 mg, and 40 mg.  

OTC famotidine (Pepcid) comes in a strength of 10 mg only. The prescription version of famotidine is available in strengths of 20 mg and 40 mg.

Can you take them together?

Taking Prilosec and Pepcid together is generally safe and may provide extra symptom relief for some people. Still, a healthcare professional may need to adjust the dosages and timing to avoid drug interactions or adverse effects.

Therefore, consider speaking with a healthcare professional before combining Prilosec and Pepcid in any strength. For safe use, it is important to follow the recommended dosage and usage instructions on the packaging or as directed by a healthcare professional.

Prescription meds for acid reflux

As well as omeprazole and famotidine, other prescription medications are available to manage acid reflux and GERD. Some common options include:

These medications reduce acid production and manage symptoms of acid reflux and GERD. It is best to talk with a healthcare professional who can help find the most suitable medication for your symptoms. 

Download the free Optum Perks Discount Card to save up to 80% on some prescription medications.


Prilosec and Pepcid are OTC medications for managing acid reflux and related symptoms. While Pepcid provides quick relief for short-term use, Prilosec takes longer to work and may be suitable for long-term symptom management.

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