Amino Acid Injections (Monograph)

Drug class: Caloric Agents
VA class: TN500

Medically reviewed by Drugs.com on Dec 23, 2024. Written by ASHP.

Introduction

Amino acid injections are caloric agents that provide the protein necessary in parenteral nutrition.

Uses for Amino Acid Injections

Amino acid injections are used in parenteral nutrition to prevent nitrogen loss or in the treatment of negative nitrogen balance when adequate nutrition by mouth, gastric or duodenal tube, or ostomy (i.e., esophagostomy, gastrostomy, jejunostomy) is impossible or undesirable (e.g., when bowel rest is needed because of GI surgery or its complications such as ileus, fistulas, or anastomotic leaks); when GI absorption of protein is impaired (e.g., in GI disorders); or when protein requirements are substantially increased (e.g., burns, sepsis, severe trauma) such that they cannot be met by enteral nutrition. Parenteral nutrition may be used to provide positive nitrogen balance and a source of calories, electrolytes, trace elements, vitamins, and other essential factors, particularly during long-term nutritional support. Parenteral nutrition is used for preoperative and postoperative patients in whom enteral nutrition is undesirable or not tolerated and in patients with GI disorders such as mechanical or functional obstruction, developmental abnormalities, malabsorption states (e.g., short-bowel syndrome), inflammatory bowel disease, or GI fistulas; in patients with hypermetabolic conditions such as extensive burns, sepsis, or severe trauma; and in patients with other conditions such as acute renal failure, hepatic insufficiency, anorexia nervosa, coma, or neoplastic disease in whom parenteral nutritional support is necessary.

Solutions of amino acids provide the protein necessary in parenteral nutrition. Amino acid injections vary in the amount of protein and nitrogen, in the presence and amount of essential and nonessential amino acids, in osmolarity, and in electrolyte concentrations. Nonprotein calories are generally provided as dextrose; however, fructose, alcohol, or fat are also used. Fat and dextrose may be used in combination, particularly during peripheral parenteral nutrition or when essential fatty acids are required. Dosage, route of administration (peripheral or central IV), and concomitant infusion of nonprotein calories depend on various factors including nutritional and metabolic status of the patient, anticipated duration of parenteral nutritional support, and tolerance of the veins.

Central venous nutrition (total parenteral nutrition, hyperalimentation) should be used when amino acid solutions are to be admixed with hypertonic dextrose and administered via a central venous catheter to promote protein synthesis in hypercatabolic or severely depleted patients or in those requiring long-term parenteral nutrition.

Peripheral parenteral nutrition should be used in individuals who are moderately catabolic or depleted and in whom the central venous route is not indicated. Dilute amino acid solutions mixed with 5 or 10% dextrose injection may be infused by peripheral vein and supplemented with fat emulsion.

Protein sparing involves peripheral infusion of dilute amino acid solutions, with or without nonprotein calories (e.g., dextrose) or electrolytes, and is used in well-nourished, mildly catabolic individuals, including routine postsurgical individuals who require only short-term parenteral nutrition.

Specialized amino acid injections (e.g., Aminess, Aminosyn RF, HepatAmine, NephrAmine, RenAmin) are available for patients (e.g., those with renal or hepatic disease) who may have specialized requirements for amino acids or who may not tolerate amino acids contained in conventional solutions.

For further information on chemistry and stability, pharmacology, uses, cautions, and dosage and administration of amino acid injections, specialized references on nutritional support and the manufacturers’ labeling should be consulted.

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