Aminohippurate sodium

Aminohippurate Sodium is a diagnostic agent used primarily to measure renal plasma flow (RPF) and effective renal plasma flow (ERPF) in individuals. It is often referred to by its abbreviation, PAH, which stands for para-aminohippuric acid, the non-sodium salt form of the compound. Aminohippurate sodium is utilized in a clinical setting to assess kidney function and to help diagnose various renal disorders.

Chemical and Pharmacological Properties

Aminohippurate sodium is a derivative of hippuric acid where a para-amino group has been added to the benzene ring. This modification allows it to be actively secreted into the renal tubules, in addition to being filtered by the glomeruli, making it an effective agent for measuring renal plasma flow.

Mechanism of Action

The primary mechanism of action of aminohippurate sodium involves its rapid secretion into the renal tubules after intravenous administration. This process is facilitated by organic anion transporters located in the renal proximal tubule. Because of its high extraction efficiency by the kidneys, the clearance of aminohippurate sodium is often used as an approximation of effective renal plasma flow (ERPF). It is important to note that ERPF represents the volume of plasma that is cleared of a substance by the kidneys per unit time, providing valuable information about renal blood flow.

Clinical Use

The main application of aminohippurate sodium is in the measurement of renal plasma flow, which is crucial for assessing the functional capacity of the kidneys. This measurement is particularly useful in diagnosing and monitoring renal diseases, evaluating potential kidney donors, and assessing the renal effects of various medications.

Procedure

The test involving aminohiphippurate sodium typically involves the intravenous administration of the compound, followed by serial blood and urine sampling. The concentration of aminohippurate sodium in these samples is then measured to calculate the renal plasma flow based on its clearance rate from the plasma.

Safety and Side Effects

Aminohippurate sodium is generally well tolerated, but side effects can occur. These may include allergic reactions, such as rash or anaphylaxis, and local reactions at the injection site, such as pain or thrombophlebitis. Due to its renal clearance, caution is advised in patients with significant renal impairment.

Conclusion

Aminohippurate sodium remains a valuable tool in the assessment of renal plasma flow, offering insights into kidney function that are essential for the diagnosis and management of renal diseases. Its use, coupled with other diagnostic tests, allows for a comprehensive evaluation of renal health.