AMINOSYN 3.5%
Clinical safety rating: caution
Comprehensive clinical and safety monograph for AMINOSYN 3.5% (AMINOSYN 3.5%).
Aminosyn 3.5% is a crystalline amino acid solution that provides essential and non-essential amino acids for protein synthesis, thereby promoting nitrogen balance and tissue repair.
| Metabolism | Amino acids are metabolized primarily in the liver via deamination, transamination, and urea cycle; some metabolism occurs in peripheral tissues. |
| Excretion | Amino acids are primarily eliminated via hepatic metabolism (deamination, transamination) and renal excretion. The renal excretion accounts for approximately 5-10% of the administered dose as unchanged amino acids; the majority is metabolized, and nitrogen is excreted as urea (80-90% of nitrogen) via urine, with minor fecal losses (<5%). |
| Half-life | The plasma half-life of individual amino acids varies; for total amino acid mixture, the terminal elimination half-life is approximately 1-2 hours in patients with normal hepatic and renal function, reflecting rapid uptake into tissues and metabolism. This half-life is clinically relevant for continuous infusion scheduling. |
| Protein binding | Amino acids have minimal protein binding (less than 10%), primarily to albumin, but binding is negligible for pharmacokinetic purposes. |
| Volume of Distribution | Volume of distribution for amino acids is approximately 0.2-0.4 L/kg, reflecting distribution primarily into extracellular fluid and lean tissue compartments. This low Vd indicates limited extravascular distribution. |
| Bioavailability | Intravenous: 100% bioavailability. Not applicable to other routes; oral administration is not indicated due to first-pass metabolism and variable absorption. |
| Onset of Action | Intravenous infusion: Onset is immediate as amino acids are directly available for protein synthesis, with clinical effects on nitrogen balance observable within 24-48 hours of initiation. |
| Duration of Action | Duration of action after infusion ceases is approximately 2-4 hours, as plasma amino acid levels decline rapidly. Continuous infusion is typically required to maintain positive nitrogen balance. |
Intravenous administration of 500 mL to 1000 mL per day as a 3.5% amino acid solution, typically infused at a rate of 1.25-2.5 mL/min (equivalent to 0.25-0.5 g amino acids/kg/day). Dose individualized based on nitrogen requirements and metabolic status.
| Dosage form | INJECTABLE |
| Renal impairment | For GFR 30-59 mL/min: reduce dose by 50% and monitor serum BUN. For GFR 15-29 mL/min: reduce dose by 75%. For GFR <15 mL/min: avoid use unless on renal replacement therapy; if used, adjust based on amino acid losses during dialysis. |
| Liver impairment | Child-Pugh Class A: no adjustment. Child-Pugh Class B: reduce dose by 50% and monitor ammonia levels. Child-Pugh Class C: avoid use or use with caution, reduce dose by 75% and monitor for hepatic encephalopathy. |
| Pediatric use | Intravenous infusion of 1-2 g amino acids/kg/day (equivalent to 28.6-57.1 mL/kg/day of 3.5% solution). For preterm infants: start at 1 g/kg/day and advance by 0.5 g/kg/day to target 2-3 g/kg/day. Titrate based on serum amino acid profiles and growth parameters. |
| Geriatric use | No specific dose adjustment based on age alone; however, elderly patients often have reduced renal function and lean body mass. Initiate at lower end of dosing range (e.g., 0.5 g amino acids/kg/day) and titrate slowly, monitoring renal function and fluid status. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for AMINOSYN 3.5% (AMINOSYN 3.5%).
| Breastfeeding | It is not known whether amino acids from Aminosyn 3.5% are excreted in human breast milk. The M/P ratio is not established. Caution should be exercised when administered to a nursing woman, as the effect on the breastfed infant is unknown. Consider the benefits of breastfeeding and the mother's need for the drug. |
| Teratogenic Risk | Aminosyn 3.5% is an amino acid solution used for parenteral nutrition. No specific teratogenic risk has been established in human pregnancy; however, maternal malnutrition may pose risks. During pregnancy, use only if clearly needed due to the risk of electrolyte imbalances, fluid overload, or metabolic disturbances that could affect the fetus. There are no adequate studies in pregnant women. The potential for fetal harm based on animal reproduction studies is not available. |
■ FDA Black Box Warning
None
| Serious Effects |
["Hypersensitivity to any component","Inborn errors of amino acid metabolism","Severe hepatic failure or hepatic coma","Severe azotemia or uremia not related to dialysis"]
| Precautions | ["Risk of metabolic acidosis","Hepatic and renal impairment may require dose adjustment","Monitor serum electrolytes, fluid balance, and ammonia levels","Do not administer if solution is cloudy or contains particulates"] |
| Food/Dietary | No direct food interactions, as this is administered intravenously. However, concurrent oral intake should be avoided until parenteral nutrition is adjusted. Monitor for refeeding syndrome if transitioning to oral nutrition. |
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| Fetal Monitoring | Monitor maternal serum electrolytes, blood glucose, acid-base status, renal function (BUN, creatinine), liver function tests, and fluid balance. Fetal monitoring should include pertinent assessments based on maternal condition, such as ultrasound for growth, amniotic fluid volume, and fetal heart rate monitoring if indicated by maternal metabolic disturbances. |
| Fertility Effects | No specific studies on fertility effects in humans. Adequate nutritional support may improve fertility in malnourished women; however, there is no evidence of direct adverse effects on fertility. In animal studies, no fertility impairment was observed at clinically relevant doses. |
| Clinical Pearls |
| AMINOSYN 3.5% is a crystalline amino acid solution used for parenteral nutrition. Monitor serum electrolytes, blood urea nitrogen (BUN), and ammonia levels. Do not administer simultaneously with blood products via same infusion line due to risk of incompatibility. Use with caution in patients with hepatic or renal impairment. Central line administration is required for concentrations >5%, but 3.5% can be infused via peripheral vein if adequately diluted and with careful monitoring for thrombophlebitis. |
| Patient Advice | This medication is given intravenously to provide protein when you cannot eat normally. · You may require regular blood tests to monitor kidney and liver function, as well as electrolyte levels. · Report any signs of infection at the IV site, such as redness, swelling, or warmth. · Do not stop or adjust the infusion rate without your healthcare provider's guidance. · Inform your doctor if you have diabetes, liver disease, or kidney disease. |