Compare Omeprazole vs. Tagamet

Head-to-head comparisons of medication uses, side effects, ratings, and more.

Prilosec
(Omeprazole)

Tagamet
(Cimetidine)

Treats heartburn and stomach ulcers. Prilosec (Omeprazole) gives you long-lasting heartburn relief. Choose the cheapest proton pump inhibitor because they all work equally well for heartburn.Relieves heartburn and acid tummy. Tagamet (Cimetidine) works well for heartburn but may not last as long or start working as quickly as other antacids.
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Reviews & ratings
Button Group. All currently active
Button Group. All currently active
5.5411558669001755Omeprazole
Reviews for Prilosec (Omeprazole)
80%
of people say Prilosec (Omeprazole) is worth it
59%
say it works well
7%
say it's a big hassle
Reviews for Tagamet (Cimetidine)
63%
17% vs. Prilosec (Omeprazole)
36%
23% vs. Prilosec (Omeprazole)
12%
5% vs. Prilosec (Omeprazole)
Side effects
OmeprazoleTagamet

The Omeprazole FDA package insert doesn’t have numbers about how common side effects are.

More about Omeprazole side effects »
  • Headache 2%
More Tagamet side effects »
How it works
OmeprazoleTagamet
Prilosec (Omeprazole) is a proton pump inhibitor (PPI). It lowers the amount of acid in your stomach, treats heartburn, and heals ulcers.Tagamet (Cimetidine) is a type of antacid called an H2 blocker. It blocks the chemical histamine, which lowers acid production in your stomach. This treats heartburn and helps ulcers heal.
Type of medication
OmeprazoleTagamet
Acid reducer
Proton pump inhibitor
Prescription or OTC
Acid reducer
Histamine blocker
Prescription or OTC
Available as
OmeprazoleTagamet
  • Extended release
  • Pill
  • Liquid
Used for (click to learn more)
OmeprazoleTagamet
Risk factors for serious side effects
OmeprazoleTagamet
    • Helicobacter pylori infection
    • Autoimmune disease
    • Being hospitalized
    • Antibiotic use
    • Osteoporosis
    • Age 50 or older
    • Using high medication doses
    • Long-term therapy (1 year or more)
    • Smoking
    • Use of other medications that weaken bones
      Detailed Prilosec (Omeprazole) risks & warnings »
        • Current kidney disease
        • Current liver disease
        • Age 50 or older
        • Current severe illness
          • Autoimmune disease
          • HIV or AIDS
          • Organ transplant
          • People without a spleen
          Detailed Tagamet (Cimetidine) risks & warnings »
          Pregnancy category
          OmeprazoleTagamet
          CFDA pregnancy category (Weigh risks vs. benefits)

          Research studies with animals found harmful effects on unborn babies. It hasn’t been properly studied in humans. The benefits might outweigh the risks even if you’re pregnant. Talk with your doctor.

          See the FDA package insert
          BFDA pregnancy category (Probably safe)

          Research studies with animals haven’t found a risk to unborn babies, but it hasn’t been properly studied in humans.

          See the FDA package insert
          Alcohol
          No specific alcohol-related info.No specific alcohol-related info.
          Food
          • Take 1 hour before a meal.
          No specific food-related info.
          Kidneys and liver
          No specific kidneys and liver-related info.
          • People with kidney disease may need to take a lower dose.
          • Tagamet (Cimetidine) can cause states of intense confusion. This is usually reversible when you stop taking Tagamet (Cimetidine). If you have kidney problems, you may need a different dose to prevent this increased risk for side effects. However, stopping Tagamet (Cimetidine) completely may be necessary.
          Sex
          No specific sex-related info.No specific sex-related info.
          Sleep
          No specific sleep-related info.No specific sleep-related info.
          Weight
          No specific weight-related info.No specific weight-related info.
          Upsides and benefits
          OmeprazoleTagamet
          • Most people can take Omeprazole without any noticeable day-to-day side effects.
          • Omeprazole lasts longer than other types of antacids (like Zantac, Pepcid, or Tums), and you only need to take it once or twice a day.
          • In studies it was better than a placebo (sugar pill) and as good as other proton pump inhibitors at treating heartburn.
          • You can take it in combination with a quick-acting antacid (like Maalox or Tums) if you need relief right away.
          • Available as both a generic and over-the-counter option, so it's pretty affordable.
          • Most people can take Cimetidine without any noticeable day-to-day side effects.
          • Cimetidine lasts longer than many other antacids like Maalox and Tums, and you only need to take it once or twice a day.
          • You can take it in combination with a quick-acting antacid (like Maalox or Tums) if you need relief right away.
          • Available as both a generic and over-the-counter option, so it's pretty affordable.
          Downsides and risks
          OmeprazoleTagamet
          • Doesn't start working as fast as some other antacids like Tums, Rolaids, or Maalox.
          • Like with other proton pump inhibitors, long-term use can cause weak or broken bones.
          • Can cause low levels of magnesium in the blood. You might need to take a magnesium supplement if you use Omeprazole long-term.
          • Although the generic is affordable, other medications might still be cheaper than Omeprazole.
          • Can interact with other drugs so be sure your doctor knows all the medicine you're taking before starting Omeprazole.
          • Other antacids like Maalox, Tums, or Rolaids often start to work more quickly than Cimetidine.
          • Medication like omeprazole (proton pump inhibitors) works better at healing and preventing stomach ulcers than medication like Cimetidine (H2 blockers).
          • Has more drug interactions than zantac and pepcid.
          • Although rare, Cimetidine can cause large breasts or impotence for men who need to use high doses for 6 months or more. It's reversible though and should go away when you stop or if you change medication.
          Tips from our pharmacists for people taking the medication
          OmeprazoleTagamet
          • Take 1 hour before a meal.
          • Don't chew or crush capsules; swallow them whole.
          • If you have trouble swallowing you can carefully open the capsules and sprinkle the inside pellets onto applesauce. Swallow the applesauce without chewing or crushing the pellets.
          • When using Omeprazole long-term, take a calcium citrate with vitamin D supplement daily to prevent bone loss. Be sure it's calcium citrate because it works the best when using a proton pump inhibitor.
          • Get a blood test for your magnesium level once a year; you may need a magnesium supplement while using Omeprazole.
          • Avoid drug interactions by telling your doctor all of the other medications or herbal supplements you take before starting Omeprazole.
          • Works best if you take it with a full glass of water.
          • Starts working in one hour.
          • If heartburn doesn't improve or lasts more than 2 weeks, talk to your doctor.
          • People with kidney disease may need to take a lower dose.
          • Tell your doctor all of the medications that you use before taking Cimetidine to avoid drug interactions.
          Learn more
          More about OmeprazoleSide effectsReviews & ratingsAlternativesFDA package insert
          More about TagametSide effectsReviews & ratingsAlternativesFDA package insert