1. Clinical Overview
L-alanyl-L-glutamine is a stable, highly soluble dipeptide composed of the amino acids L-alanine and L-glutamine. In its 20% w/v injectable form, it serves as a superior source of glutamine for parenteral nutrition. Glutamine is a conditionally essential amino acid crucial for rapidly dividing cells (enterocytes, lymphocytes), nitrogen transport, and maintaining acid-base balance. It becomes essential during severe metabolic stress (sepsis, trauma, major surgery) when endogenous synthesis cannot meet demand. The dipeptide form overcomes the instability and poor solubility of free L-glutamine in aqueous solutions, allowing for safe and effective intravenous administration.
| Onset | Duration | Bioavailability |
|---|---|---|
| Immediate upon intravenous infusion, with plasma levels rising proportionally to infusion rate. | Pharmacodynamic effects (e.g., nitrogen balance improvement, immune modulation) are sustained for several hours post-infusion, dependent on the metabolic state of the patient. | 100% following intravenous administration. The dipeptide is rapidly cleaved by tissue and plasma dipeptidases (e.g., membrane-bound alanyl-aminopeptidase) into its constituent amino acids. |
2. Mechanism of Action
L-alanyl-L-glutamine acts as a stable, bioavailable precursor to replenish depleted glutamine pools. During severe catabolic stress, glutamine demand exceeds synthesis, leading to a deficiency. This deficiency impairs gut barrier function, immune competence, and nitrogen balance. Administration of this dipeptide provides glutamine which: 1) Serves as a primary respiratory fuel for enterocytes and colonocytes, maintaining intestinal mucosal integrity and preventing bacterial translocation. 2) Acts as a nitrogen donor for nucleotide synthesis in rapidly proliferating cells like lymphocytes and macrophages, supporting immune function. 3) Serves as a precursor for glutathione (a key antioxidant). 4) Acts as a nitrogen transporter between tissues, facilitating ureagenesis and renal ammoniagenesis.
3. Indications & Uses
- As a component of parenteral nutrition for adult patients with severe catabolic states (e.g., major burns, polytrauma, severe sepsis).
- For patients undergoing major gastrointestinal surgery where oral/enteral intake is not possible or insufficient for >5-7 days.
4. Dosage & Administration
Adult Dosage: 1.5 to 2.0 mL/kg body weight per day (equivalent to 0.3 to 0.4 g L-alanyl-L-glutamine/kg/day or 0.2 to 0.26 g glutamine/kg/day). Maximum daily dose: 500 mL (100 g dipeptide) for a 70 kg patient. Must be mixed with other amino acids in parenteral nutrition solutions; the dipeptide should not exceed 20% of the total amino acid content of the final admixture.
Administration: FOR INTRAVENOUS USE ONLY. Must be diluted before infusion. The 20% w/v solution is concentrated. Typically, the required daily volume is added to a bag containing the total parenteral nutrition (TPN) solution (amino acids, glucose, lipids, electrolytes, trace elements). Administer via a central venous catheter or a large peripheral vein as part of a TPN infusion over 12-24 hours. Never administer as a bolus injection. Ensure strict aseptic technique during preparation and administration.
5. Side Effects
Common side effects may include:
- Nausea (if infusion rate is too rapid).
- Local reactions at injection site: pain, phlebitis (more common with peripheral infusion).
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Antiepileptics (e.g., Valproate) | May have synergistic effect in increasing plasma ammonia levels. | Moderate |
| Corticosteroids | May counteract the protein-sparing effects of glutamine due to catabolic action. | Moderate |
| Chemotherapeutic agents (e.g., Methotrexate) | Theoretical interaction; glutamine may affect turnover of cells in gut mucosa. Evidence is conflicting. | Low |
7. Patient Counselling
- This medication will be administered by healthcare professionals in a hospital.
- Do not request to adjust the infusion rate.
- Report any discomfort at the IV site immediately.
- Inform the doctor of any history of liver or kidney disease.
8. Toxicology & Storage
Overdose: Symptoms of overdose would be related to metabolic disturbances: hyperammonemia (lethargy, vomiting, cerebral edema), metabolic acidosis, hyperglycemia, fluid overload, and electrolyte imbalances (hyperkalemia, hyperphosphatemia).
Storage: Store below 25°C. Do not freeze. Keep the container in the outer carton to protect from light. The diluted solution in the TPN bag should be used immediately. If storage is necessary, hold at 2-8°C for not more than 24 hours. Discard any unused portion. Do not use if the solution is discolored or contains particulate matter.