Axid AR (Nizatidine) - Oral

Warning:

The Food and Drug Administration (FDA) hasn't assigned black box warnings to Axid AR (nizatidine).

What Is Axid AR?

Axid AR (nizatidine) is an over-the-counter (OTC) medication for heartburn. As a histamine H2 inhibitor, it works by blocking the H2 receptors (binding sites) in the stomach. This leads to less stomach acid secretion.

OTC nizatidine is available in a tablet dosage form. A prescription version of nizatidine is also available in a capsule dosage form. The higher-strength prescription nizatidine can also be used for other stomach and gut problems.

Drug Facts

Generic Name: Nizatidine

Brand Name(s): Axid AR

Drug Availability: Nizatidine tablets are over-the-counter (OTC), but nizatidine capsules are prescription products.

Therapeutic Classification: Histamine H2-blocker

Available Generically: OTC nizatidine isn't available as a generic product, but the nizatidine prescription is only available in a generic version.

Controlled Substance: No

Administration Route: Oral (by mouth)

Active Ingredient: Nizatidine

Dosage Form(s): The OTC version is available as tablets, but the prescription version is available as capsules.

What Is Axid AR Used For?

Axid AR is used for heartburn.

Heartburn is a burning feeling or sensation in your chest or throat. Experiencing heartburn from acid reflux is very common every once in a while. It's estimated that more than 60 million people in the United States (U.S.) have heartburn at least once a month—with more than 15 million people having heartburn daily.

Acid reflux occurs when your gastric juices (stomach acid) escape your esophagus. The esophagus is a tube moving food from your mouth to your stomach.

How to Take Axid AR

Axid AR can be used to relieve or prevent heartburn.

If you're already experiencing heartburn, take one Axid AR tablet by mouth with a full glass of water right away.

To prevent heartburn, you'll still take one Axid AR tablet by mouth with a full glass of water—but take it within an hour before the food or beverage that triggers your heartburn. You can even take the tablet right before this food or drink.

Storage

When you pick up Axid AR from the pharmacy, store the medication between 68 degrees and 77 degrees Fahrenheit (F). This is typically room temperature range. Axid AR should also be protected from light.

Keep your medications tightly closed and out of the reach of children and pets, ideally locked in a cabinet or closet.

Avoid pouring unused and expired drugs down the drain or in the toilet. Instead, visit the FDA's website to learn where and how to discard all unused and expired medications. You can also find disposal boxes in your area. Ask your pharmacist or healthcare provider if you have any questions about the best ways to dispose of your medications.

If you plan to travel with Axid AR, get familiar with your final destination's regulations. Checking with the U.S. embassy or consulate might be a helpful resource. If you have a prescription from your healthcare provider for Axid AR, make a copy of it. Keeping Axid AR in its original container is also a good idea to. If there's a pharmacy label with your name on the original packaging, keep it on there. Ask your pharmacist or healthcare provider if you have any questions about traveling with your medicine.

How Long Does Axid AR Take to Work?

Axid AR might start working right away. However, for some people, the medication may need 30 to 60 minutes to kick in.

Off-Label Uses

While prescription nizatidine capsules may have other uses, experts don't typically choose nizatidine for these uses anymore. Some of these uses include:

  • Peptic ulcer disease (PUD): PUD may include ulcers in the stomach or gut (intestines).
  • Esophagitis from gastroesophageal reflux disease (GERD): Esophagitis is irritation or inflammation (swelling) of the esophagus (the tube that connects the mouth to your stomach). GERD is a severe and chronic (long-term) acid reflux condition.

What Are the Side Effects of Axid AR?

This is not a complete list of side effects, and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your pharmacist or a healthcare provider. You may report side effects to the FDA at fda.gov/medwatch or 800-FDA-1088.

Common Side Effects

Common side effects with Axid AR may include:

Severe Side Effects

Reach out to your healthcare provider if the above common side effects become severe or don't go away. Get medical help right away if you develop the following serious side effects of a severe allergic reaction:

  • Breathing difficulties
  • Itchiness
  • Rash
  • Wheezing

Call 911 if your symptoms feel life-threatening.

Long-Term Side Effects

Some nizatidine products may contain small amounts of N-nitrosodimethylamine (NDMA). While NDMA is also found in small amounts in the environment, too much NDMA may increase your risk of developing cancers.

The FDA advises manufacturers to test their nizatidine products. The manufacturer should recall the product if it has more than the safe limit of 96 nanograms per day.

Report Side Effects

Axid AR may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Axid AR Should I Take?

Drug Content Provided and Reviewed by IBM Micromedex®

The dose medicines in this class will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of these medicines. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For cimetidine:
    • For oral dosage forms (solution and tablets):
      • To treat duodenal or gastric ulcers:
        • Older adults, adults, and teenagers—300 milligrams (mg) four times a day, with meals and at bedtime. Some people may take 400 or 600 mg two times a day, on waking up and at bedtime. Others may take 800 mg at bedtime.
        • Children—20 to 40 mg per kilogram (kg) (9.1 to 18.2 mg per pound) of body weight a day, divided into four doses, taken with meals and at bedtime.
      • To prevent duodenal ulcers:
        • Older adults, adults, and teenagers—300 mg two times a day, on waking up and at bedtime. Instead some people may take 400 mg at bedtime.
        • Children—Dose must be determined by your doctor.
      • To treat heartburn, acid indigestion, and sour stomach:
        • Adults and teenagers—100 to 200 mg with water when symptoms start. The dose may be repeated once in twenty-four hours. Do not take more than 400 mg in twenty-four hours.
        • Children—Dose must be determined by your doctor.
      • To prevent heartburn, acid indigestion, and sour stomach:
        • Adults and teenagers—100 to 200 mg with water up to one hour before eating food or drinking beverages you expect to cause symptoms. Do not take more than 400 mg in twenty-four hours.
        • Children—Dose must be determined by your doctor.
      • To treat conditions in which the stomach produces too much acid:
        • Adults—300 mg four times a day, with meals and at bedtime. Your doctor may change the dose if needed.
        • Children—Dose must be determined by your doctor.
      • To treat gastroesophageal reflux disease:
        • Adults—800 to 1600 mg a day, divided into smaller doses. Treatment usually lasts for 12 weeks.
        • Children—Dose must be determined by your doctor.
    • For injection dosage form:
      • To treat duodenal ulcers, gastric ulcers or conditions in which the stomach produces too much acid:
        • Older adults, adults, and teenagers—300 mg injected into muscle, every six to eight hours. Or, 300 mg injected slowly into a vein every six to eight hours. Instead, 900 mg may be injected slowly into a vein around the clock at the rate of 37.5 mg per hour. Some people may need 150 mg at first, before beginning the around-the-clock treatment.
        • Children—5 to 10 mg per kg (2.3 to 4.5 mg per pound) of body weight injected into a vein or muscle, every six to eight hours.
      • To prevent stress-related bleeding:
        • Older adults, adults, and teenagers—50 mg per hour injected slowly into a vein around the clock for up to 7 days.
        • Children—Dose must be determined by your doctor.
  • For famotidine:
    • For oral dosage forms (suspension, tablets, chewable tablets, and oral disintegrating tablets):
      • To treat duodenal ulcers:
        • Older adults, adults, and teenagers—40 milligrams (mg) once a day at bedtime. Some people may take 20 mg two times a day.
        • Children—Dose must be determined by your doctor.
      • To prevent duodenal ulcers:
        • Older adults, adults, and teenagers—20 mg once a day at bedtime.
        • Children—Dose must be determined by your doctor.
      • To treat gastric ulcers:
        • Older adults, adults, and teenagers—40 mg once a day at bedtime.
        • Children—Dose must be determined by your doctor.
      • To treat heartburn, acid indigestion, and sour stomach:
        • Adults and teenagers—10 mg with water when symptoms start. The dose may be repeated once in twenty-four hours. Do not take more than 20 mg in twenty-four hours.
        • Children—Dose must be determined by your doctor.
      • To prevent heartburn, acid indigestion, and sour stomach:
        • Adults and teenagers—10 mg taken one hour before eating a meal you expect to cause symptoms. The dose may be repeated once in twenty-four hours. Do not take more than 20 mg in twenty-four hours.
        • Children—Dose must be determined by your doctor.
      • To treat conditions in which the stomach produces too much acid:
        • Older adults, adults, and children—20 mg every six hours. Your doctor may change the dose if needed.
        • Children—Dose must be determined by your doctor.
      • To treat gastroesophageal reflux disease:
        • Older adults, adults, and teenagers—20 mg two times a day, usually for up to 6 weeks.
        • Children weighing more than 10 kg (22 pounds)—1 to 2 mg per kilogram (kg) (0.5 to 0.9 mg per pound) of body weight a day, divided into two doses.
        • Children weighing less than 10 kg (22 pounds)—1 to 2 mg per kg (0.5 to 0.9 mg per pound) of body weight a day, divided into three doses.
    • For injection dosage form:
      • To treat duodenal ulcers, gastric ulcers, or conditions in which the stomach produces too much acid:
        • Older adults, adults, and teenagers—20 mg injected into a vein, every twelve hours.
        • Children—Dose must be determined by your doctor.
  • For nizatidine:
    • For oral dosage forms (capsules and oral solution):
      • To treat duodenal or gastric ulcers:
        • Older adults, adults, and teenagers—300 milligrams (mg) once a day at bedtime. Some people may take 150 mg two times a day.
        • Children—Dose must be determined by your doctor.
      • To prevent duodenal ulcers:
        • Adults and teenagers—150 mg once a day at bedtime.
        • Children—Dose must be determined by your doctor.
      • To prevent heartburn, acid indigestion, and sour stomach:
        • Adults and teenagers—75 mg taken thirty to sixty minutes before eating a meal you expect to cause symptoms. The dose may be repeated once in twenty-four hours.
        • Children—Dose must be determined by your doctor.
      • To treat gastroesophageal reflux disease:
        • Adults and teenagers—150 mg two times a day.
        • Children—Dose must be determined by your doctor.
  • For ranitidine:
    • For oral dosage forms (syrup, tablets, effervescent tablets):
      • To treat active duodenal ulcers:
        • Older adults, adults, and teenagers—150 milligrams (mg) two times a day. Some people may take 300 mg once a day at bedtime.
        • Children and infants—2 to 4 mg per kilogram (kg) (1 to 2 mg per pound) of body weight twice a day. However, the total dose will not be more than 300 mg a day.
      • To maintain healing of duodenal ulcers:
        • Older adults, adults, and teenagers—150 mg once a day at bedtime.
        • Children and infants—2 to 4 mg per kg (1 to 2 mg per pound) of body weight once a day. However, the total dose will not be more than 150 mg a day.
      • To treat erosive esophagitis:
        • Older adults, adults, and teenagers—150 mg four times a day
        • Children and infants—5 to 10 mg per kg (2.3 to 4.6 mg per pound) of body weight per day, usually divided and given in two doses during the day.
      • To maintain healing of erosive esophagitis:
        • Older adults, adults, and teenagers—150 mg twice a day
        • Children and infants—Dose must be determined by your doctor.
      • To treat benign gastric ulcers:
        • Older adults, adults, and teenagers—150 mg two times a day.
        • Children and infants—2 to 4 mg per kg (1 to 2 mg per pound) of body weight twice a day. However, the total dose will not be more than 300 mg a day.
      • To maintain healing of gastric ulcers:
        • Older adults, adults, and teenagers—150 mg once a day at bedtime.
        • Children and infants—2 to 4 mg per kg (1 to 2 mg per pound) of body weight once a day. However, the total dose will not be more than 150 mg a day.
      • To treat heartburn, acid indigestion, and sour stomach:
        • Adults and teenagers—150 mg with water when symptoms start. The dose may be repeated once in twenty-four hours. Do not take more than 300 mg in twenty-four hours.
        • Children—Dose must be determined by your doctor.
      • To prevent heartburn, acid indigestion, and sour stomach:
        • Adults and teenagers—150 mg with water taken thirty to sixty minutes before eating a meal or drinking beverages you expect to cause symptoms. Do not take more than 300 mg in twenty-four hours.
        • Children—Dose must be determined by your doctor.
      • To treat some conditions in which the stomach produces too much acid:
        • Older adults, adults, and teenagers—150 mg two times a day. Your doctor may change the dose if needed.
        • Children—Dose must be determined by your doctor.
      • To treat gastroesophageal reflux disease:
        • Older adults, adults, and teenagers—150 mg two times a day. Your dose may be increased if needed.
        • Children and infants—5 to 10 mg per kg (2.3 to 4.6 mg per pound) of body weight per day, usually divided and given in two doses during the day.
    • For injection dosage form:
      • To treat duodenal ulcers, gastric ulcers, or conditions in which the stomach produces too much acid:
        • Older adults, adults, and teenagers—50 milligrams (mg) injected into a muscle every six to eight hours. Or, 50 mg injected slowly into a vein every six to eight hours. Instead, you may receive 6.25 mg per hour injected slowly into a vein around the clock. However, most people will usually not need more than 400 mg a day.
      • To treat duodenal or gastric ulcers:
        • Children—2 to 4 mg per kilogram (kg) (1 to 2 mg per pound) of body weight per day, usually divided and injected slowly into a vein every six to eight hours. However the total dose will not be more than 50 mg every six to eight hours.

Modifications

The following modifications (changes) should be kept in mind when using Axid AR (nizatidine):

Severe allergic reaction: Avoid using nizatidine if you have a known allergy to it or its ingredients. Ask your pharmacist or healthcare provider for a complete list of the ingredients if you're unsure.

Pregnancy: In rat animal studies, nizatidine was found to have no negative effects on the fetus. We don't know enough about the safety and effectiveness of nizatidine in pregnant people and their unborn fetuses.

Discuss with your healthcare provider if you plan to become pregnant or are pregnant. They will help you weigh the benefits and risks of using nizatidine during your pregnancy.

Breastfeeding: Nizatidine is present in human breast milk. Since only a small amount of nizatidine is present in breast milk, negative effects on the nursing baby are unlikely.

Talk with your healthcare provider if you plan to breastfeed; your healthcare provider will help you weigh the benefits and risks of nizatidine while nursing. They can also discuss the different ways available to feed your baby.

Older adults over 65: There are no response differences to nizatidine between older and younger adults. However, older adults with several medical conditions or taking several medications should use caution. In addition, older adults might be more sensitive to side effects from medications.

Children: According to the OTC label for Axid AR, people 12 years and older may take nizatidine.

Kidney problems: Individuals with kidney problems may not be able to clear the medication from their bodies as quickly. This means the medicine stays in the body longer and can have increased side effects. For this reason, your healthcare provider will likely recommend a lower nizatidine dosage for you if you have severe kidney impairment.

Missed Dose

Axid AR (nizatidine) is sometimes only taken once in a while to relieve heartburn immediately or prevent acid reflux from specific foods and beverages. So, it's unlikely that you'll miss your as-needed Axid AR dose.

If you regularly take nizatidine on a schedule, take this medication as your healthcare provider recommended. However, if you accidentally forgot your nizatidine dose, take it as soon as you remember. If it's already close to your next scheduled dose, skip the missed dose and take the following dose at your next scheduled dosing time. Don't try to double up to make up for the missed dose.

Try to find ways that work for you to help yourself remember to keep your appointments and take your medication routinely. The medication might be less effective if you miss too many scheduled nizatidine doses.

However, the OTC Axid AR product is usually only recommended for 14 days. Reach out to your healthcare provider if you have questions about how long to take your medication.

Overdose: What Happens If I Take Too Much Axid AR?

In animal studies, high nizatidine doses resulted in the following side effects:

  • Diarrhea
  • Pinpoint pupils (part of the eye that lets light pass through)
  • Salivation (making saliva or spit)
  • Teary eyes
  • Vomiting

In humans, there is limited information available about nizatidine overdoses.

If you think you're experiencing an overdose or life-threatening symptoms, seek immediate medical attention.

What Happens If I Overdose on Axid AR?

If you think you or someone else may have overdosed on Axid AR, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses or isn't breathing after taking Axid AR, call 911 immediately.

Precautions

Drug Content Provided and Reviewed by IBM Micromedex®

Limited testing has found unacceptable levels of a probable human carcinogen, N-nitrosodimethylamine (NDMA), in some ranitidine medicines

Some tests may be affected by this medicine. Tell the doctor in charge that you are taking this medicine before:

  • You have any skin tests for allergies.
  • You have any tests to determine how much acid your stomach produces.

Remember that certain medicines, such as aspirin, and certain foods and drinks (e.g., citrus products, carbonated drinks) irritate the stomach and may make your problem worse.

Cigarette smoking tends to decrease the effect of H2-blockers by increasing the amount of acid produced by the stomach. This is more likely to affect the stomach's nighttime production of acid. While taking H2-blockers, stop smoking completely, or at least do not smoke after taking the last dose of the day.

Drinking alcoholic beverages while taking an H2-receptor antagonist has been reported to increase the blood levels of alcohol. You should consult your health care professional for guidance.

Check with your doctor if your ulcer pain continues or gets worse.

What Are Reasons I Shouldn’t Take Axid AR?

Before taking Axid AR (nizatidine), talk with your healthcare provider if any of the following applies to you:

  • Severe allergic reaction: If you have a severe allergic reaction to nizatidine or its components (ingredients), then nizatidine isn't a viable option.
  • Pregnancy: Nizatidine in animal studies didn't find any negative effects on the fetus. However, there is limited information about nizatidine's safety and effects on the unborn fetus. Discuss with your healthcare provider the benefits and risks of using nizatidine while pregnant.
  • Breastfeeding: Nizatidine is present in human breast milk. Since only a small amount of nizatidine is present in breast milk, negative effects on the nursing baby are unlikely. Talk with your healthcare provider about the benefits and risks of nizatidine while nursing.
  • Children: According to the OTC label for Axid AR, people 12 years and older may take nizatidine.
  • Older adults over 65: There are no response differences to nizatidine between older and younger adults. However, older adults should use caution.

What Other Medications Interact With Axid AR?

Axid AR (nizatidine) generally makes your stomach fluids less acidic.

This may break down the protective covering of certain medications, such as Atelvia (risedronate delayed-release) for osteoporosis (condition of weak and brittle bones). In a less acidic environment, Atelvia is quickly released through the weakened protective layer and absorbed into your bloodstream. This high Atelvia level might put you at a higher risk of side effects.

A basic (higher pH) environment may also result in less absorption of other medications into your bloodstream, making these medications less effective. For example, H2-blockers—like nizatidine—may decrease atazanavir protease inhibitor levels. You may find atazanavir as the brand name Evotaz, which also contains cobicistat. Evotaz is typically used with Truvada (tenofovir disoproxil fumarate/emtricitabine) or Descovy (tenofovir alafenamide/emtricitabine) to treat human immunodeficiency virus (HIV) in certain situations.

Talk with your pharmacist or healthcare provider for more detailed information about medication interactions with Axid AR.

And be sure to talk with your healthcare provider about any other medicines you take or plan to take, including over-the-counter, nonprescription products, vitamins, herbs, or plant-based medicines.

What Medications Are Similar?

Axid AR (nizatidine) is an H2 blocker.

Some nizatidine products might have a chemical called N-nitrosodimethylamine (NDMA). In small amounts, your body can get rid of NDMA without any problems. But, in high amounts, NDMA might cause cancer. The FDA advises manufacturers to test their nizatidine products. The manufacturer should recall the product if it has more than the safe limit of 96 nanograms per day.

The following H2 blockers have been discontinued due to concerns about contamination with NDMA:

  • Pepcid or Pepcid AC (famotidine)
  • Tagamet (cimetidine)

Cimetidine is still available under the brand name Tagamet HB.

Frequently Asked Questions

  • Where is nizatidine available?

    Nizatidine tablets are available OTC as Axid AR. Nizatidine is also available in higher-strength prescription capsules. You'll likely find nizatidine at your local retail pharmacy.

  • How much does nizatidine cost?

    Nizatidine is available as OTC Axid AR and in a generic prescription version. So, this will likely save you on costs.

    If cost is a concern, other potentially helpful resources may include: NeedyMeds, FundFinder, Simplefill, BenefitsCheckUp, Medicare Rights Center, State Pharmaceutical Assistance Programs (SPAPs), and Rx Outreach.

  • Is nizatidine more effective than other H2 blockers?

    While most people might have a favorite H2 blocker, nizatidine is as effective as the other H2 blockers—like famotidine.

  • Is nizatidine as good as proton pump inhibitors?

    H2 blockers—like nizatidine—are effective for heartburn from gastroesophageal reflux disease (GERD). However, if you have a more serious condition—like esophagitis problems from GERD, then the more preferable options are proton pump inhibitors (PPIs), such as Nexium (esomeprazole).

  • Can I get cancer from nizatidine?

    Some nizatidine products contain a chemical called N-nitrosodimethylamine (NDMA). In small amounts, your body can get rid of it without any issues. Large amounts, however, might cause cancer.

    The FDA is advising manufacturers to test their nizatidine products. If the product has more than the safe limit of 96 nanograms per day, the manufacturer should recall the product.

How Can I Stay Healthy While Taking Axid AR?

If you're taking Axid AR, heartburn may negatively affected your quality of life.

Having heartburn from acid reflux has its challenges. You may have tried different approaches or treatments. Refer below for some general suggestions to prevent and manage heartburn.

  • Take acid reflux-related medications as recommended by your healthcare provider.
  • Avoid certain foods and beverages that trigger your heartburn. Examples may include spicy or fried food, coffee, alcohol, or chocolate.
  • Wear comfortable-fitting clothing, especially around the stomach area.
  • Avoid large meals.
  • Take your time to eat. Don't eat too fast.
  • Don't lay down right away after eating.
  • Don't eat right before bedtime.
  • Try to quit smoking if you smoke.
  • Have a healthy diet and an exercise routine to help manage your weight. If you're overweight, losing weight may relieve your heartburn symptoms.

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended as a replacement for medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

13 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Axid AR (nizatidine tablet) label.

  2. Food and Drug Administration. Nizatidine capsule label.

  3. MedlinePlus. GERD.

  4. National Institute of Diabetes and Digestive and Kidney Diseases. Definition & facts for GER & GERD.

  5. NIH MedPlus Magazine. Heartburn: what you need to know.

  6. MedlinePlus. Nizatidine.

  7. Food and Drug Administration. FDA updates and press announcements on NDMA in Zantac (ranitidine).

  8. Drugwatch. NDMA.

  9. LactMed. Nizatidine.

  10. Prescribers Digital Reference. Nizatidine—drug summary.

  11. HIV.gov. Guidelines for the use of antiretroviral agents in adults and adolescents with HIV.

  12. Tougas G, Armstrong D. Efficacy of H2 receptor antagonists in the treatment of gastroesophageal reflux disease and its symptoms. Canadian Journal of Gastroenterology and Hepatology. 1997;11(Suppl B):51B-54B.

  13. Zeid Y, Confer J. Standards of care for GERD. U.S. Pharmacist. 2016;21(12):24-29.

By Ross Phan, PharmD, BCACP, BCGP, BCPS
Ross is a writer for Verywell with years of experience practicing pharmacy in various settings. She is also a board-certified clinical pharmacist and the founder of Off Script Consults.