AMINOSYN II 3.5% M
Clinical safety rating: caution
Comprehensive clinical and safety monograph for AMINOSYN II 3.5% M (AMINOSYN II 3.5% M).
Provides essential and nonessential amino acids for protein synthesis, serving as substrates for anabolic processes in parenteral nutrition.
| Metabolism | Amino acids are metabolized via transamination, deamination, and incorporation into proteins; primarily hepatic and renal pathways. |
| Excretion | Aminosyn II 3.5% M is a crystalline amino acid solution. Amino acids are primarily eliminated by metabolic utilization for protein synthesis and energy production. Excess amino acids undergo deamination, with nitrogen excreted as urea in urine via renal route. Fecal and biliary excretion are negligible. Approximately 80-90% of infused nitrogen is recovered as urea in urine in patients with normal renal function. |
| Half-life | The terminal elimination half-life of amino acids from the infusion mixture is not uniformly defined; however, individual amino acids have half-lives ranging from 10 to 30 minutes. For the mixture, the effective half-life is clinically considered to be approximately 1-2 hours, reflecting rapid metabolic clearance. In renal impairment, the half-life may be prolonged due to reduced urea clearance. |
| Protein binding | Amino acids exhibit minimal to no protein binding; albumin binding is negligible (<5%). Free amino acids circulate in plasma. |
| Volume of Distribution | The volume of distribution (Vd) of amino acids approximates total body water, about 0.5-0.6 L/kg. This reflects distribution into extracellular and intracellular compartments. Clinical meaning: Initial dilution occurs in plasma and interstitial fluid, then uptake into cells for metabolism. |
| Bioavailability | Intravenous: 100% bioavailability as it is directly administered into the bloodstream. Not applicable for oral or other routes due to extensive first-pass metabolism; if given orally, amino acids would be absorbed but subject to hepatic metabolism. |
| Onset of Action | Intravenous infusion: Provision of amino acids for protein synthesis occurs immediately as infusion begins; measurable increases in plasma amino acid concentrations within 15-30 minutes. Clinical effects on nitrogen balance are observed within 24-48 hours of continuous infusion. |
| Duration of Action | The duration of action is limited to the infusion period and shortly thereafter. Amino acids are continuously cleared from plasma, and protein synthesis stimulation persists for several hours post-infusion. To maintain positive nitrogen balance, continuous or intermittent daily infusions are required. Effects on nitrogen balance last 24-48 hours after cessation. |
Intravenous infusion of 1.2 to 2.2 g amino acids per kg per day, adjusted to meet metabolic and nutritional requirements. Typical adult dose: initial infusion rate of 50 mL/hour, increasing to 125 mL/hour (4.4 g amino acids per hour) based on tolerance. Not for direct peripheral administration without supplementation of electrolytes and/or dextrose.
| Dosage form | INJECTABLE |
| Renal impairment | For acute or chronic renal impairment: restrict total nitrogen intake to 0.4-0.8 g nitrogen/kg/day (2.5-5.0 g amino acids/kg/day) based on GFR. GFR <15 mL/min: use specialized renal amino acid solutions; if using AMINOSYN II, reduce dose by 50% and monitor BUN and electrolytes closely. |
| Liver impairment | Child-Pugh Class A: no adjustment needed. Child-Pugh B: reduce dose by 25-50% based on tolerance and monitoring of ammonia. Child-Pugh C: use with extreme caution; consider branched-chain amino acid-enriched formulations; AMINOSYN II not recommended due to high aromatic amino acid content. |
| Pediatric use | Weight-based dosing: 1.5-3.0 g amino acids/kg/day (0.06-0.13 g/kg/hour) as continuous IV infusion. For neonates and infants: start at 1.5-2.0 g/kg/day, advance by 0.5 g/kg/day to goal of 2.5-3.0 g/kg/day; monitor serum ammonia, BUN, and glucose. Maximum infusion rate: 0.1 g/kg/hour. |
| Geriatric use |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for AMINOSYN II 3.5% M (AMINOSYN II 3.5% M).
| Breastfeeding | Excretion of amino acids into breast milk has not been studied; however, endogenous amino acids are normally present in breast milk. The M/P ratio is unknown. Caution is advised; consider the benefits of breastfeeding and the mother's clinical need for parenteral nutrition. |
| Teratogenic Risk | Aminosyn II 3.5% M is a crystalline amino acid solution used for parenteral nutrition. No teratogenic effects have been reported in human studies; however, adequate animal reproductive studies have not been conducted. Use during pregnancy only if clearly needed. Fetal risks are considered low when used as indicated for maternal nutritional support. |
■ FDA Black Box Warning
Not for intravenous infusion in patients with inborn errors of amino acid metabolism; solutions are hypertonic and may cause vein damage; contains aluminum that may be toxic with prolonged use.
| Serious Effects |
Hypersensitivity to amino acids, severe hepatic disease, inborn errors of amino acid metabolism, severe uremia (without dialysis), and metabolic acidosis.
| Precautions | Monitor fluid and electrolyte balance, acid-base status, blood glucose, serum ammonia, and liver function; risk of hyperammonemia, metabolic acidosis, and aluminum toxicity; use with caution in renal/hepatic impairment. |
| Food/Dietary | No direct food interactions as this is an intravenous solution. However, enteral nutrition should be initiated as soon as feasible to maintain gut integrity. Avoid concurrent administration of lipid emulsions in the same IV line unless using a Y-site connector with compatible fluids. |
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| Elderly patients: use lower end of adult dosing (1.2-1.5 g amino acids/kg/day) due to decreased renal and hepatic function. Monitor fluid status, BUN, creatinine, and electrolytes closely. Infusion rate should not exceed 0.15 g/kg/hour to avoid metabolic disturbances. |
| Fetal Monitoring | Monitor maternal serum electrolytes, acid-base balance, blood urea nitrogen, ammonia, liver function tests, and glucose levels. Fetal monitoring with ultrasound and non-stress tests is recommended in pregnant patients receiving parenteral nutrition to assess fetal growth and well-being. |
| Fertility Effects | No adverse effects on fertility have been reported. As a nutritional supplement, it supports general health and may improve fertility status in malnourished individuals. No specific reproductive toxicity studies are available. |
| Clinical Pearls | Aminosyn II 3.5% M is a parenteral amino acid solution used for protein supplementation in patients unable to tolerate enteral nutrition. Contains a balanced mixture of essential and nonessential amino acids with added electrolytes (acetate and phosphate). Monitor serum electrolytes, renal function, and acid-base status. Avoid in severe hepatic encephalopathy or inborn errors of amino acid metabolism. Infuse via central line; peripheral administration may cause thrombophlebitis due to hypertonicity. Use with caution in renal impairment to avoid azotemia. |
| Patient Advice | This medication provides protein nutrition through an IV line when you cannot eat normally. · Your doctor will monitor your blood tests regularly, including kidney function and electrolyte levels. · Do not stop or adjust the infusion rate yourself; it must be given exactly as prescribed. · Report any signs of infection at the IV site (redness, swelling, pain) or symptoms like nausea, headache, or confusion. · Tell your healthcare provider if you have a history of liver or kidney problems. |