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Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice.
Brand Name
Ammonia N 13
Generic Name
Nh3n13
Active Ingredient
Ammonia N-13Category
Radioactive Diagnostic Agent [EPC]
Variants
5
Different strengths and dosage forms
| Strength | Form | Route | NDC |
|---|---|---|---|
| 37.5 mCi/mL | INJECTION | INTRAVENOUS | 13267-456 |
| 37.5 mCi/mL | INJECTION | INTRAVENOUS | 24275-0385 |
| 37.5 mCi/mL | INJECTION | INTRAVENOUS |
This page is for informational purposes only and does not replace medical advice. Before using any prescription or over-the-counter medication for Ammonia N 13, you must consult a qualified healthcare professional.
| 37.5 mCi/mL | INJECTION | INTRAVENOUS | 75913-113 |
| 37.5 mCi/mL | INJECTION | INTRAVENOUS | 40089-113 |
Detailed information about Ammonia N 13
Ammonia N-13 is a radioactive diagnostic agent used in Positron Emission Tomography (PET) imaging to evaluate myocardial perfusion (blood flow to the heart) in patients with suspected or known coronary artery disease.
The standard adult dose for Ammonia N-13 depends on the specific imaging protocol used by the medical facility and the patient's body weight. According to the FDA-approved labeling, the typical dose ranges are as follows:
The total cumulative dose for a single imaging session (rest and stress) usually does not exceed 40 mCi. Healthcare providers calculate the dose to ensure the lowest possible radiation exposure that still provides high-quality diagnostic images (the ALARA principle: As Low As Reasonably Achievable).
Ammonia N-13 is not routinely used in pediatric populations for coronary artery disease, as this condition is rare in children. However, it may be used in specialized cases for evaluating congenital heart defects or other cardiac anomalies.
Because Ammonia N-13 is primarily eliminated via radioactive decay (half-life of 10 minutes), formal dosage adjustments for patients with kidney disease are generally not required. However, since the metabolites are eventually cleared through the bladder, patients with severe renal impairment may have a slightly higher radiation dose to the bladder wall. Clinicians may encourage increased fluid intake and frequent voiding after the procedure.
There are no specific dosage adjustments provided for patients with liver impairment. The rapid decay of the Nitrogen-13 isotope minimizes the impact of altered liver metabolism on the overall safety profile of the drug.
In clinical trials, no overall differences in safety or effectiveness were observed between elderly patients and younger patients. Dosage is typically the same as the standard adult dose, though the patient's ability to undergo the 'stress' portion of the test must be carefully evaluated.
Ammonia N-13 is administered only by trained healthcare professionals (nuclear medicine technologists or radiologists) in a hospital or imaging center setting.
Since Ammonia N-13 is administered by a healthcare professional during a scheduled medical procedure, a 'missed dose' in the traditional sense does not occur. If the procedure is interrupted or the drug is not administered, the scan will simply be rescheduled. Because the drug decays so fast, it cannot be 'saved' for later in the day.
An overdose of Ammonia N-13 is highly unlikely due to the strict controls in radiopharmaceutical preparation. However, if a larger-than-intended dose were given, the primary concern would be increased radiation exposure. Because the half-life is only 10 minutes, the radiation levels drop by 99% within 70 minutes. In the event of an error, the patient should be encouraged to hydrate and void frequently to minimize radiation to the bladder.
> Important: Follow your healthcare provider's instructions regarding fasting and caffeine avoidance to ensure the accuracy of your Ammonia N-13 PET scan.
Ammonia N-13 is generally very well tolerated. Because it is a diagnostic tracer given in 'trace' amounts (micrograms), it does not have the systemic pharmacological effects that a typical heart medication would. Most patients do not feel anything from the injection itself.
However, the procedure associated with the injection often has side effects:
In rare instances, patients may experience mild reactions to the solution in which the Ammonia N-13 is dissolved:
Ammonia N-13 is intended for diagnostic use only. It must be administered in a clinical setting where emergency equipment is available to treat potential (though rare) allergic reactions or cardiac events during the stress-testing portion of the procedure.
No FDA black box warnings for Ammonia N-13.
Ammonia N-13 contributes to a patient’s overall long-term cumulative radiation exposure. Healthcare providers must ensure that the dose administered is the minimum required to obtain a clear image. This is particularly important for patients who have had multiple recent radiological procedures (CT scans, X-rays, or other nuclear medicine tests).
Although ammonia is a naturally occurring metabolite, the preparation contains other ingredients for stability and pH balancing. Patients with a history of severe allergies to other radiopharmaceuticals or IV solutions should inform their doctor. Facilities are required to have resuscitation equipment and trained staff on hand during administration.
There are no drugs that are strictly 'contraindicated' because of a chemical reaction with Ammonia N-13. However, certain drugs are contraindicated because they mask the diagnostic results of the test:
Beta-blockers slow the heart rate and reduce the heart's oxygen demand. If a patient is taking these during a 'stress' PET scan, it may prevent the heart from reaching the necessary level of stress, potentially hiding areas of poor blood flow. Doctors often ask patients to hold these for 24-48 hours before the test.
There are very few absolute contraindications to Ammonia N-13 itself, as it is a naturally occurring molecule given in trace amounts. However, the following apply:
These are conditions where the doctor must weigh the benefits of the scan against the potential risks:
Ammonia N-13 should be administered to a pregnant woman only if clearly needed. All radiopharmaceuticals have the potential to cause fetal harm due to radiation exposure. The risk is highest during the first trimester when organogenesis (organ formation) occurs.
It is not known if Ammonia N-13 is excreted in human milk. However, because of the risk of radiation exposure to the nursing infant, the following precautions are recommended:
Ammonia N-13 acts as a blood flow tracer. Its uptake into the myocardium is governed by the Na+/K+ ATPase pump and, to a lesser extent, by passive diffusion. Once inside the myocyte (heart cell), the Nitrogen-13 ammonia is rapidly metabolized by the enzyme glutamine synthetase into [N-13] glutamine.
Because glutamine is a large, polar molecule, it cannot easily diffuse back out of the cell. This "metabolic trapping" ensures that the concentration of radioactivity in the heart muscle remains stable for the duration of the PET scan (about 10-20 minutes). The amount of trapped N-13 is directly proportional to the myocardial blood flow (MBF), making it an ideal tracer for quantifying perfusion.
Ammonia N-13 has no significant pharmacodynamic effects at the doses used for imaging. It does not change heart rate, blood pressure, or cardiac output. Its only 'effect' is the emission of positrons, which are used for detection by the imaging equipment. The onset of action is immediate (as soon as it reaches the heart), and the duration of the 'effect' (radioactivity) is limited by its physical half-life.
Common questions about Ammonia N 13
Ammonia N-13 is a radioactive tracer used during a Positron Emission Tomography (PET) scan to evaluate blood flow to the heart muscle. It is primarily used to diagnose coronary artery disease by identifying areas of the heart that are not receiving enough blood. Additionally, it helps doctors determine if heart tissue is permanently damaged or if it can be saved by procedures like bypass surgery. The test provides a highly detailed 'map' of the heart's circulation, which is more accurate than traditional stress tests. Because of its short half-life, it is only used in specialized medical facilities.
Most patients experience no side effects directly from the Ammonia N-13 injection itself, as it is given in very small, trace amounts. Some people may feel a slight coldness or stinging at the site where the IV was inserted. If side effects do occur, they are usually mild and temporary, such as a brief headache, nausea, or dizziness. It is important to remember that many 'side effects' reported during the test are actually caused by the stress-testing medications (like adenosine) or fasting, rather than the Ammonia N-13. Serious allergic reactions are extremely rare but are always monitored for by the medical staff.
You should not consume alcohol for at least 24 hours before your Ammonia N-13 PET scan. Alcohol can affect your heart rate and blood pressure, which may interfere with the accuracy of the rest and stress images. While there is no dangerous chemical interaction between alcohol and the tracer, the goal of the test is to see how your heart functions in a 'clean' state. After the procedure is finished and the radioactivity has decayed (usually about 2 hours), there is no specific restriction on alcohol. However, you should always follow the specific recovery instructions provided by your cardiologist.
Ammonia N-13 involves exposure to ionizing radiation, which can potentially harm a developing fetus. Therefore, it is generally not recommended during pregnancy unless the diagnostic information is critical for the mother's life and cannot be obtained any other way. If you are pregnant or think you might be, you must inform your doctor before the procedure. Healthcare providers will typically use alternative tests like an echocardiogram, which does not use radiation, for pregnant patients. If the scan is performed, precautions are taken to use the lowest possible dose and to ensure the mother stays well-hydrated.
Ammonia N-13 works almost instantly once it is injected into your vein. It travels through the bloodstream and reaches the heart muscle within seconds. The PET scanner begins capturing images immediately or within 1 to 3 minutes after the injection. Because the radioactivity decays so rapidly (half of it is gone every 10 minutes), the 'window' for imaging is very short. The entire imaging portion of the test usually lasts between 10 and 20 minutes per injection. You will not feel the drug 'working,' but the cameras will be able to see your blood flow right away.
Ammonia N-13 is not a medication that you take on a regular basis; it is a one-time injection used only for a diagnostic test. Therefore, there is no 'stopping' the medication or risk of withdrawal. Once the injection is given, the body naturally clears the radioactivity through a process called radioactive decay. Within about 70 to 100 minutes, virtually all of the radioactivity has disappeared from your body. You do not need to take any special steps to 'taper' off the drug, as it is a short-acting diagnostic tool rather than a therapeutic treatment.
Because Ammonia N-13 is administered by medical professionals in a controlled hospital setting, you cannot 'miss a dose' in the way you might miss a pill at home. If you are unable to make it to your appointment, the drug cannot be used later because it loses its radioactivity very quickly (it has a 10-minute half-life). If you miss your scheduled PET scan appointment, the facility will have to order or produce a fresh batch of the drug for a new time. If the injection is not successful during the procedure, the technologist will handle the rescheduling or adjustment.
No, Ammonia N-13 does not cause weight gain. It is a diagnostic tracer given in a single, microscopic dose for a PET scan. It does not contain calories, nor does it affect your metabolism, appetite, or hormones in a way that would lead to weight changes. Any weight changes you may be experiencing would be related to other factors, such as your underlying heart condition, other medications you are taking, or lifestyle factors. If you have concerns about weight gain, you should discuss them with your primary care physician or cardiologist.
While Ammonia N-13 does not have 'drug-drug interactions' in the traditional sense, many medications can interfere with the accuracy of the PET scan results. Drugs like beta-blockers, calcium channel blockers, and nitrates can change how blood flows to the heart, potentially 'hiding' a blockage from the camera. Most importantly, caffeine and certain asthma medications (like theophylline) must be avoided because they block the effects of the stress agents used during the test. You must provide your doctor with a full list of your medications so they can tell you which ones to stop taking temporarily before your scan.
Ammonia N-13 is a radiopharmaceutical that is produced by various specialized facilities and cyclotrons, and it is not marketed as a 'brand name' vs. 'generic' drug in the way that pills like Lipitor or Advil are. It is typically referred to simply by its chemical name, Ammonia N-13. Multiple different companies and hospitals may have FDA approval to produce it. Because it must be made fresh on-site or nearby due to its 10-minute half-life, you won't find it at a retail pharmacy. It is provided as part of the cost of the PET imaging procedure at the hospital.
True allergic reactions to Ammonia N-13 are exceedingly rare because ammonia is a substance naturally produced by the human body. However, reactions to the sterile saline or the manufacturing process can occur:
While highly unlikely with Ammonia N-13, serious reactions can occur during any medical procedure involving an IV injection.
> Warning: Stop the procedure and alert the medical staff immediately if you experience any of the following:
The primary long-term consideration for any radiopharmaceutical is the cumulative risk of radiation exposure.
There are no FDA Black Box Warnings for Ammonia N-13. It is considered a safe and standard diagnostic tool when used by qualified professionals.
Report any unusual symptoms, even if they seem minor, to your healthcare provider or the imaging technologist during your procedure.
If the IV needle is not correctly positioned, the Ammonia N-13 can leak into the surrounding tissue (extravasation). Because it is radioactive, this can cause localized tissue irritation and may result in a 'non-diagnostic' scan (the images will not be clear). If you feel burning or pain at the injection site, tell the technologist immediately.
It is important to distinguish between the risks of the drug and the risks of the procedure. If Ammonia N-13 is used during a 'stress' test, the stress itself (whether from a treadmill or a drug like dobutamine) carries risks of heart attack, arrhythmias, or severe hypertension. These risks are managed by the supervising cardiologist.
There are no long-term lab tests (like blood counts or liver enzymes) required after receiving Ammonia N-13. However, during the procedure:
Ammonia N-13 itself does not cause drowsiness or impairment. Most patients are safe to drive themselves home after the procedure. However, if a patient received a sedative for anxiety or if they feel weak after the stress-testing portion, they should wait until they feel fully recovered before driving.
There is no known direct interaction between alcohol and Ammonia N-13. However, patients are typically asked to fast and avoid various substances before the test. Alcohol should be avoided for at least 24 hours prior to the scan to ensure the heart's resting state is not artificially altered.
As this is a one-time diagnostic injection, there is no 'discontinuation' or withdrawal syndrome. The drug naturally 'discontinues' itself through radioactive decay within about an hour of administration.
> Important: Discuss all your medical conditions, especially any history of asthma or heart rhythm problems, with your healthcare provider before starting the Ammonia N-13 procedure.
Similar to beta-blockers, these can blunt the heart's response to stress and may interfere with the accuracy of the perfusion map generated by the Ammonia N-13.
Long-acting nitrates (like Isosorbide mononitrate) can dilate coronary arteries and improve blood flow temporarily. This might make an area of 'ischemia' look 'normal' on the PET scan. Patients are usually instructed to hold these medications on the morning of the test.
This medication should be stopped 48 hours before the test if a pharmacological stress agent is being used, as it can significantly potentiate the effects of adenosine, leading to dangerously low blood pressure or heart block.
Ammonia N-13 does not typically interfere with standard blood chemistry or hematology tests. However, the presence of radioactivity in the body can trigger highly sensitive radiation monitors (such as those at airports or international borders) for 2-4 hours after the injection. Patients may be provided with a 'travel letter' if they plan to fly immediately after their scan.
> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking, especially those for heart disease, asthma, or erectile dysfunction.
There is no known cross-sensitivity between Ammonia N-13 and iodinated contrast media (used in CT scans) or gadolinium (used in MRI). Patients allergic to 'dye' used in other scans can typically receive Ammonia N-13 safely, as it does not contain iodine or gadolinium.
> Important: Your healthcare provider will evaluate your complete medical history, including any history of radiation therapy, before prescribing an Ammonia N-13 PET scan.
Safety and effectiveness in pediatric patients have not been extensively established through large-scale clinical trials. Use in children is usually limited to specialized tertiary care centers. The main concern is the higher sensitivity of developing tissues to radiation. Doses are scaled down significantly based on body surface area or weight.
Ammonia N-13 is frequently used in patients over age 65, as this is the population most affected by coronary artery disease.
In patients with reduced kidney function (low GFR), the biological clearance of the N-13 glutamine metabolite may be slowed. This does not affect the quality of the PET images but does slightly increase the radiation dose to the bladder. No dose adjustment is needed, but aggressive hydration is advised.
Since the liver is a site of ammonia metabolism (urea cycle), severe liver failure could theoretically alter the distribution of the tracer. However, in clinical practice, this has not been shown to significantly impact the diagnostic utility of the heart scan.
> Important: Special populations require individualized medical assessment to ensure the diagnostic benefits of the PET scan outweigh the risks of radiation.
| Parameter | Value |
|---|---|
| Bioavailability | 100% (Intravenous) |
| Protein Binding | Minimal |
| Physical Half-life | 9.97 minutes |
| Tmax (Heart) | 1–3 minutes post-injection |
| Metabolism | Glutamine Synthetase (to N-13 glutamine) |
| Excretion | Radioactive decay (99% in 70 min); Renal (metabolites) |
Ammonia N-13 is classified as a Radiopharmaceutical, Positron Emitting Diagnostic Agent. It is part of a group of PET tracers that includes Fluorodeoxyglucose (FDG), Rubidium-82, and Oxygen-15 Water. Among these, Ammonia N-13 is considered the 'clinical gold standard' for measuring absolute myocardial blood flow due to its high extraction fraction and excellent image resolution.