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13c urea and citric acid (Oral route)

13C Urea, SIT-rik AS-id

Commonly used brand name(s)

In the U.S.

  • IDkit Hp

Available Dosage Forms:

  • Tablet
  • Powder

Uses For 13c urea and citric acid

13C urea and citric acid are medicines used in a diagnostic test called Exalenz BreathID® non-invasive breath test. It is a test that analyzes a breath sample before and after taking 13C-enriched urea to help diagnose patients with infections in the stomach caused by a bacteria called H. pylori.

Both of these medicines are taken by the mouth. If any H. pylori bacteria are present in the stomach, they will cause the 13C urea to be broken down into carbon dioxide gas. When you breathe out by the mouth, the amount of carbon dioxide can be measured by Exalenz BreathID® Hp System to detect whether the bacteria are in your stomach.

These medicines are available only with your doctor's prescription.

Before Using 13c urea and citric acid

In deciding to use a diagnostic test, any risks of the test must be weighed against the good it will do. This is a decision you and your doctor will make. Also, other things may affect test results. For this test, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to 13c urea and citric acid or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.


Appropriate studies have not been performed on the relationship of age to the effects of 13C urea and citric acid in the pediatric population. Safety and efficacy have not been established.


No information is available on the relationship of age to the effects of 13C urea and citric acid in geriatric patients.


Pregnancy Category Explanation
All Trimesters C Animal studies have shown an adverse effect and there are no adequate studies in pregnant women OR no animal studies have been conducted and there are no adequate studies in pregnant women.

Breast Feeding

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Interactions with Medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or nonprescription (over-the-counter [OTC]) medicine.

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this diagnostic test. Make sure you tell your doctor if you have any other medical problems, especially:

  • Achlorhydria—The lack of acid in the stomach may interfere with the results of this test.
  • Gastrectomy (removal of the stomach by surgery), partial or total—Use is not recommended in these patients.
  • Phenylketonuria—13c urea and citric acid contains phenylalanine, which can make this condition worse.

Proper Use of 13c urea and citric acid

Exalenz BreathID® non-invasive breath test is a diagnostic test that analyzes a breath sample before and after taking 13C-enriched urea to help identify patients with H. pylori infection.

Your doctor will start the breath test by collecting your breath samples using the BreathID® Hp device. You will drink a mixed solution of 13C-urea tablet and citric acid powder. You must drink the solution within 2 hours after mixing it. Then, you have to breathe normally via the cannula while the test is being performed.

Do not eat for at least 1 hour before taking the mixed solution.

If the mixed solution has large particles after mixing it for 5 minutes, do not use it and open a new kit.

Precautions While Using 13c urea and citric acid

If you are taking antibiotics, proton pump inhibitors (eg, omeprazole, lansoprazole), or medicines containing bismuth, these may interact with the test. Your doctor will ask you to stop taking them for at least 2 weeks before the test.

13c urea and citric acid Side Effects

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur:

Incidence not known
  • Fast heartbeat
  • fever
  • hives, itching, or rash
  • hoarseness
  • irritation
  • joint pain, stiffness, or swelling
  • redness of the skin
  • swelling of the eyelids, face, lips, hands, or feet
  • tightness in the chest
  • troubled breathing or swallowing

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

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