Aminohippurate Sodium (Intravenous)

Aminohippurate sodium is a non-toxic drug which, when introduced into the bloodstream intravenously, acts as a testing agent that can be measured to assess renal function.

Overview

Aminohippurate sodium is utilized in medicine as a diagnostic agent to measure kidney function. Its diagnostic value is that the clearance of the drug from the bloodstream acts as a measure of the renal plasma filtering capabilities of the kidneys, called the effective renal plasma flow (ERPF). Aminohippurate sodium is the anhydrous salt from para-aminohippuric acid, or PAH.

The drug is water soluble, has a pKa of 3.83 and is lipid insoluble. Aminohippurate sodium is also used to measure the transport maximum of the drug through the renal tubes. As aminohippurate sodium is added to the bloodstream, it passes through the kidneys as a result of the renal tubular secretion function. This closely related test is referred to as TmPAH. These tests are administered only by medical providers in a clinic or hospital setting. Care must be taken through constant monitoring of the patient's condition while this drug is being administered.

Condition treated

  • Effective renal plasma flow (ERPF)
  • Renal transport maximum (TmPAH)

Type of medicine

  • Intravenous injection
  • Continuous infusion

Side effects

Side effects may be caused by hypersensitivity to the drug or substances that it is made from or comes in contact with. Medical providers should be alerted to any noticeable side effects that occur and are even slightly bothersome. Many side effects will pass without any intervention, but some may need medical intervention if they are severe. Often, administration of this drug can make people feel like they have to urinate or defecate soon after the infusion has begun. Other side effects of an aminohippurate sodium injection can include:

  • Feeling warm
  • Nausea
  • Cramps
  • Vomiting
  • Vasomotor disturbance
  • Anaphylaxis
  • Flushing and tingling of skin
  • Angioedema
  • Urticaria (Hives)

The rate of incidence is not known for these side effects:

  • Cough
  • Difficulty in swallowing
  • Dizziness
  • Itching and welts
  • Fast heartbeat
  • Redness and swelling of the face, eyelids, lips, tongue, throat, sex organs, hands, upper chest, legs, or feet
  • Muscle cramps
  • Chest tightness
  • Excessive weakness or tiredness
  • Shortness of breath
  • Wheezing

Your medical care team can advise you if there are any ways to lessen or prevent side effects from happening in the first place. If you have any questions regarding side effects, be sure to consult with your medical provider before the use of this drug.

Dosage

It is important to only use aminohippurate sodium under direction from a physician, in conjunction with a renal capacity test. This drug comes packaged in a 10 mL quantity sterile and non-preserved injectable aqueous solution. It has a pH between 6.7 and 7.6. The solution is 2 grams aminohippurate sodium, water, and sodium hydroxide to adjust the pH level. It is only administered in a healthcare facility such as a hospital or specialized clinic.

Single injection methods often lead to inaccurate test results, so infusion is recommended to maintain a fixed rate of the drug to measure effective renal plasma flow (ERPF). To achieve the optimum level of this drug in the system, an initial dose of six to 10 mg/kg is used, followed by an infusion of 10 to 24 mg/min.

For the transport maximum test (TmPAH), a 40 to 60 mg/100 mL concentration is usually needed. In either test, medical care providers will constantly monitor the levels of the drug in your bloodstream. Administration of the drug needs to be gradual, to lessen the stress on the body's circulatory system.

Interactions

It is vitally important that you make your physician aware of all of the prescription and nonprescription medications you take before aminohippurate sodium is used for testing your renal function. This is to guard against a possible interaction between this drug and other medicines or supplements you may be taking. What you report to the physician may lead your health care team to advise a modification of your medication schedule while getting tested with this drug.

There are drugs that adversely affect the accuracy of renal clearance measurement tests with aminohippurate sodium, including:

  • Procaine
  • Sulfonamides
  • Thiazolesulfone
  • Probenecid

Consult with your doctor about what food or liquids you can consume close to the testing period. Avoid using tobacco or alcohol before the test, as it also may cause interactions with the testing drug.

Certain comorbid medical issues may affect the ability to conduct this medical test safely, including:

  • Congestive heart failure
  • Heart disease

This is because the use of this test with aminohippurate sodium may worsen these conditions. Care must be taken to ensure that the volume increase in your plasma is done gradually, as a quick increase in plasma volume can cause congestive heart failure. Double check that your medical provider knows all of your diagnoses before embarking on a renal capacity test. This is to assure that a full assessment of the advisability of the test is undertaken.

Warnings

Talk with your doctor regarding both the risks and benefits of renal testing with aminohippurate sodium and in your case, whether the test has a high probability of yielding accurate results. Your doctor will also give consideration to the following conditions and factors:

Possible allergic reactions

If you are allergic to latex, let your doctor know before you have a test using this drug, as the vial stopper is made of dry natural rubber which comes from latex. For latex-sensitive individuals, use of a drug that has been exposed to a rubber stopper has a high probability of causing an allergic reaction.

Before any test or treatment, it is always advisable to tell your medical care team about any adverse reactions or allergies you have to certain medications or substances, such as preservatives, food ingredients, dyes, or animal products. This way your physician can determine whether it is likely that you will have a reaction to this and other drugs that may be used in conjunction with it.

Geriatric use

Safety studies on the use of aminohippurate sodium in the geriatric cohort have not revealed any complications that affect the appropriateness of this drug's use. It has been established in the limited testing completed that there are no discernable differences in drug response between the geriatric population and their younger counterparts.

Pediatric use

The advisability of testing with aminohippurate sodium has not been studied in the pediatric patient population. Therefore, its effectiveness and safety have not been proven with this population.

Use while pregnant or breastfeeding

Aminohippurate sodium is in the C category for all trimesters of pregnancy. This means that animal studies have shown harmful effects of the use of the drug during pregnancy, or that no rigorous testing of the drug has been performed on animals and humans. Use of this drug during pregnancy is not advised.

There are no scientifically adequate studies that determine the risk of this drug to breastfeeding infants. Patients who are breastfeeding and considering the use of this drug should discuss the risks and benefits of the use of this drug with their physician. Studies have also not been done to assess any impact the drug has on fertility.

Potentiality of carcinogenic effects

To date, no comprehensive studies have been done in animals or humans to assess the possibility of increased cancer risk from use of this drug.

Storage

Each 10 mL vial of non-preserved and sterile aqueous solution should ideally be stored at 77°F (25°C). The acceptable temperature range for aminohippurate sodium storage is from 59 to 86°F (15 to 30°C).

Summary

Aminohippurate sodium is used as a diagnostic agent in kidney function testing that is conducted only under the close and careful supervision of a physician. This solution is given by injection or continuous intervenous administration for immediate delivery to the bloodstream.

Low doses of aminohippurate sodium are used for the effective renal plasma flow test (ERPF), but larger amounts of the drug are needed to conduct the transport maximum test of renal capacity (TmPAH). At either dose, a steady slow and continuous intervenous administration of the drug is recommended. If low plasma levels of the drug are used in the test, the kidneys' filtering mechanisms should be able to clear practically all of the drug out of the bloodstream in one trip.

Aminohippurate sodium is generally well tolerated when administered in a medical setting for the purposes of renal function testing. Exceptions to tolerance include individuals with heart disease, congestive heart failure, or latex allergies. No difference in test accuracy has been noted between the general population and the geriatric cohort. Use during pregnancy is not recommended, and caution is advised for use while breastfeeding.

Side effects of the drug's use may include nausea, cramps, vomiting, hives, feeling warm, vasomotor disturbances, anaphylaxis, angioedema, and itching. Other side effects may occur and should be reported to medical personnel right away.

Resources
Last Reviewed:
December 10, 2017
Last Updated:
April 04, 2018