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Pentagastrin (Diagnostic)

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Pentagastrin (Diagnostic)

US Brand Names

• Peptavlon

Canadian Brand Names

• Peptavlon


Pentagastrin (pen-ta-GAS-trin) is a testing agent used to help diagnose problems or disease of the stomach. This test determines how much acid your stomach produces.

How the test is done: The dose of pentagastrin is based on body weight and must be determined by your doctor. The pentagastrin is injected beneath the skin. Ten or 15 minutes later, the contents of the stomach are emptied and tested for the amount of the contents and the amount of acid in the contents. The procedure may be repeated several times.

Pentagastrin is used only under the supervision of a doctor. It is available in the following dosage form:


    • Injection (U.S. and Canada)

Before Having This Test

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, test results may be affected by other things. For pentagastrin, the following should be considered:


Tell your doctor if you have ever had any unusual or allergic reaction to pentagastrin. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.


Studies on effects in pregnancy have not been done in either humans or animals.


It is not known whether pentagastrin passes into the breast milk. Although most medicines pass into breast milk in small amounts, many of them may be used safely while breast-feeding. Mothers who are receiving this diagnostic test and wish to breast-feed should discuss this with their doctor.


Studies on this medicine have been done only in adult patients, and there is no specific information comparing use of pentagastrin in children with use in other age groups.

Older adults

Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of pentagastrin in the elderly with use in other age groups.

Other 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. When you will be given pentagastrin, it is especially important that your health care professional know if you are taking any of the following:

    • Antacids or

    • Anticholinergics (medicine for abdominal or stomach spasms or cramps) or

    • Cimetidine (e.g., Tagamet) or

    • Famotidine (e.g., Pepcid) or

    • Nizatidine (e.g., Axid) or

    • Omeprazole (e.g., Prilosec) or

    • Ranitidine (e.g., Zantac)-These medicines decrease the effect that pentagastrin has on the production of stomach acid, and the test may not work

Other medical problems

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

    • Gallbladder problems or

    • Liver disease or

    • Pancreatitis (inflammation of the pancreas) (severe) or

    • Stomach ulcer (severe or bleeding)-Pentagastrin may make these conditions worse

Preparation for This Test

Unless otherwise directed by your doctor:

    • Do not eat anything beginning the night before and do not drink anything for at least four hours before the test. Having food or liquid in the stomach may affect the interpretation of the test results.

    • Do not take antacids on the morning of the test. To do so may decrease the effect of pentagastrin and affect the test results.

    • For 24 hours before the test, do not take any anticholinergics (medicine for abdominal or stomach spasms or cramps), cimetidine, famotidine, nizatidine, ranitidine, or any other medicine that decreases stomach acid. Do not take omeprazole for 96 hours (4 days) before the test.

Along with its needed effects, pentagastrin may cause some unwanted effects. Although the side effects usually are rare, when they do occur they may require medical attention.

Check with your health care professional immediately if either of the following side effects occurs:


Skin rash or hives.

Other side effects may occur that usually do not need medical attention. These side effects should go away as the effects of the medicine wear off. However, check with your doctor if any of the following side effects continue or are bothersome:

More common

(usually disappear within 15 minutes after injection) Gas; nausea or vomiting; stomach pain; urge to have bowel movement.

Less common or rare

Blurred vision; chills; dizziness, faintness, or lightheadedness; drowsiness; fast heartbeat; feeling of heaviness of arms and legs; headache; increased sweating; numbness, tingling, pain, or weakness in hands or feet; shortness of breath; unusual tiredness; unusual warmth or flushing of skin.

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

July 14, 1993

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