AMINOHIPPURATE SODIUM
Clinical safety rating: caution
Comprehensive clinical and safety monograph for AMINOHIPPURATE SODIUM (AMINOHIPPURATE SODIUM).
Aminohippurate sodium is a diagnostic agent used to measure effective renal plasma flow (ERPF) by competitive inhibition of tubular secretion of para-aminohippurate (PAH) via organic anion transporters (OAT1 and OAT3) in the proximal tubule, allowing clearance calculations.
| Metabolism | Not metabolized; excreted unchanged by renal tubular secretion and glomerular filtration. |
| Excretion | Primarily renal: ~90% excreted unchanged by tubular secretion; <5% fecal. |
| Half-life | Terminal elimination half-life is approximately 0.5–1.0 hour; used to measure effective renal plasma flow (ERPF). |
| Protein binding | ~20% bound to plasma proteins (mainly albumin). |
| Volume of Distribution | Vd ~0.2 L/kg; reflects confinement to extracellular fluid and plasma. |
| Bioavailability | IV: 100%; oral: not available as no oral formulation is marketed. |
| Onset of Action | IV: immediate within 1–2 minutes; oral: not clinically used. |
| Duration of Action | IV: ~30 minutes for diagnostic effect; rapidly cleared from plasma. |
For measurement of effective renal plasma flow (ERPF): 0.2 mL/kg of a 20% solution (40 mg/kg) administered intravenously over 1-2 minutes, followed by continuous intravenous infusion of 0.5 mL/min of a solution containing 4.5 g aminohippurate sodium in 500 mL normal saline (9 mg/mL) to maintain stable plasma levels.
| Dosage form | INJECTABLE |
| Renal impairment | No standard dose adjustment for GFR; however, interpretation of test results is affected by renal dysfunction. In patients with severe renal impairment (eGFR <30 mL/min/1.73 m²), the clearance measurement may be unreliable. |
| Liver impairment | No specific dose adjustments in hepatic impairment. Use with caution in severe hepatic disease due to potential altered metabolism. |
| Pediatric use | For measurement of ERPF: 0.2 mL/kg of a 20% solution (40 mg/kg) intravenously over 1-2 minutes, then continuous infusion at a rate adjusted to maintain plasma levels of 1-2 mg/dL; typical infusion rate is 0.5 mL/min of a dilute solution (e.g., 9 mg/mL) in older children, with lower rates in infants. |
| Geriatric use | No specific dose adjustment; use with caution due to age-related decline in renal function. Monitor infusion rate to avoid fluid overload in elderly patients with compromised cardiac function. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for AMINOHIPPURATE SODIUM (AMINOHIPPURATE SODIUM).
| Breastfeeding | Excretion in human milk unknown; consider risk-benefit. M/P ratio: unknown. |
| Teratogenic Risk | No adequate human studies; animal reproduction studies not conducted. Risk cannot be ruled out. Use only if clearly needed. |
| Fetal Monitoring | Monitor renal function, urine output, and signs of hypersensitivity during infusion. |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to aminohippurate sodium or any component of the formulation","Anuria or severe renal impairment (contraindicated for ERPF measurement)","Known allergy to sulfonamides (potential cross-reactivity)"]
| Precautions | ["Use with caution in patients with known hypersensitivity to aminohippurate or related compounds","Monitor for allergic reactions including anaphylaxis","Risk of false low ERPF values in patients with impaired renal function","Avoid extravasation as it may cause tissue irritation"] |
| Food/Dietary | No specific food interactions. Maintain normal hydration status as directed by the physician. |
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| Fertility Effects | No known effects on fertility. |
| Clinical Pearls |
| Administer intravenously for accurate measurement of effective renal plasma flow (ERPF). Ensure adequate hydration to avoid urinary tract stasis. Monitor for hypersensitivity reactions, especially in patients with sulfonamide allergy. Use with caution in patients with severe renal impairment (eGFR < 30 mL/min) as clearance may be unreliable. |
| Patient Advice | This medication is used to measure how well your kidneys are functioning. · You will receive an injection into your vein and will be asked to collect urine samples over a specific time period. · Drink plenty of fluids before and after the test to stay well-hydrated. · Inform your healthcare provider if you have any allergies, especially to sulfa drugs. · Report any symptoms like rash, hives, or difficulty breathing immediately. |