Usage
- L-Glutamine is prescribed for sickle cell disease to reduce acute complications in adults and children 5 years and older. It is also used as a nutritional supplement for short bowel syndrome, particularly in patients receiving specialized nutritional support along with growth hormone. Additionally, it’s used as a nutritional supplement in critical illness, trauma, and post-surgical recovery. It’s also used for glutamine deficiency, which can exacerbate intestinal permeability (a condition linked to Irritable Bowel Syndrome, where substances pass through the intestinal wall too readily).
- Pharmacological classification: Amino acid, nutritional supplement.
- Mechanism of action: While not fully understood, in sickle cell disease, L-glutamine likely addresses oxidative stress. It’s a precursor for glutathione, a powerful antioxidant. For short bowel syndrome and other conditions, it provides a crucial energy source for intestinal cells, promoting cell growth and repair. It also modulates the immune response.
Alternate Names
- L-Glutamine is sometimes referred to simply as glutamine.
- Brand Name: Endari.
How It Works
- Pharmacodynamics: L-Glutamine serves as a crucial energy source for rapidly dividing cells, particularly those in the gut and immune system. It supports intestinal integrity, immune function, and protein synthesis. It also acts as a precursor for the synthesis of other amino acids, nucleotides, and the antioxidant glutathione. In sickle cell disease, it helps reduce oxidative stress and inflammation.
- Pharmacokinetics: L-Glutamine is readily absorbed from the gastrointestinal tract. It’s metabolized primarily in the intestines, liver, and kidneys. It’s converted to glutamate and ammonia.
- Mode of action: L-Glutamine enters cells via amino acid transporters. Inside the cell, it participates in various metabolic pathways, including energy production, protein synthesis, and glutathione synthesis.
- Receptor binding, enzyme inhibition, or neurotransmitter modulation: While L-Glutamine itself does not directly bind to receptors, its metabolite glutamate acts as an excitatory neurotransmitter.
- Elimination pathways: Primarily renal excretion. It can also undergo conversion to other metabolites before excretion.
Dosage
Standard Dosage
Adults:
- Short Bowel Syndrome: 30 grams per day, divided into 6 doses of 5 grams each, taken at 2–3-hour intervals with meals or snacks while awake for up to 16 weeks.
- Sickle Cell Disease: 30 grams per day, divided into two doses of 15 grams each. For those weighing between 30 to 65 kilograms, 20 grams daily (10 grams twice daily); for those weighing less than 30 kilograms, 10 grams daily (5 grams twice daily).
- Dietary Supplement: 5 to 30 grams per day, divided into doses.
Children:
- Sickle Cell Disease: Children 5 years and older: dosing based on weight as described above.
- Dietary Supplement: 0.7 grams/kg body weight daily (safety of higher doses is not established). Doses must be determined by a doctor for children under 5 for both Sickle Cell Disease and Short Bowel Syndrome.
- Pediatric safety considerations: Doses should be carefully adjusted based on weight and age. Close monitoring is needed, and consultation with a pediatric specialist is highly recommended.
Special Cases:
- Elderly Patients: Dosage adjustments may be needed due to potentially reduced kidney or liver function. Close monitoring is essential.
- Patients with Renal Impairment: Routine monitoring of renal function is recommended. Dose adjustment might be necessary.
- Patients with Hepatic Dysfunction: Routine monitoring of liver function is recommended as L-Glutamine is metabolized to glutamate and ammonia. Dose adjustments may be needed.
- Patients with Comorbid Conditions: Careful consideration should be given for patients with diabetes, liver disease, bipolar disorder, or those on protein-restricted diets.
Clinical Use Cases
- Intubation/Surgical Procedures/Mechanical Ventilation/ICU Use: L-Glutamine is often included in parenteral nutrition regimens for critically ill patients to support metabolic needs and gut integrity. Dosage depends on patient-specific factors and clinical status. Generally, 15-30 grams daily.
- Emergency Situations: No specific emergency dosage recommendations.
Dosage Adjustments
- Dose modifications may be necessary based on renal/hepatic function, other metabolic disorders, or the presence of concomitant medications.
Side Effects
Common Side Effects
- Constipation, nausea, headache, abdominal pain, cough, pain in extremities, back pain, chest pain.
Rare but Serious Side Effects
- Allergic reactions (rash, hives, itching, swelling).
- Liver damage.
- Worsening of mania or hypomania in individuals with bipolar disorder.
Long-Term Effects
- Insufficient data on long-term effects. However, theoretical concerns about ammonia buildup exist with chronic high doses in those with liver or kidney issues.
Adverse Drug Reactions (ADR)
- Severe allergic reactions requiring urgent medical attention.
Contraindications
- Hypersensitivity to L-glutamine.
- Severe liver disease or renal impairment.
- Reye’s syndrome.
- Conditions requiring protein restriction.
Drug Interactions
- Anticonvulsants: L-Glutamine may reduce the effectiveness of anticonvulsant medications.
- Lactulose: L-Glutamine may reduce lactulose’s effectiveness in lowering ammonia levels.
- Hormonal contraceptives: May reduce the effectiveness of hormonal contraceptives.
- Cyclosporine: Contraindicated due to increased risk of liver toxicity.
- Rifampin: May reduce the effectiveness of L-Glutamine.
- Warfarin: Careful monitoring required due to potential altered anticoagulant effects.
Pregnancy and Breastfeeding
- Pregnancy Safety Category: C. There’s no reliable information on using it medicinally in larger amounts during pregnancy. Avoid use.
- Fetal risks: Insufficient human data to assess risks. Animal studies are lacking.
- Breastfeeding: Excretion in breast milk and effects on infants are unknown. Exercise caution and prioritize breastfeeding benefits.
Drug Profile Summary
- Mechanism of Action: Provides energy for rapidly dividing cells; supports gut and immune function; reduces oxidative stress (in sickle cell disease).
- Side Effects: Constipation, nausea, headache, abdominal pain; rarely, allergic reactions or liver damage.
- Contraindications: Hypersensitivity, severe liver/kidney disease, Reye’s syndrome.
- Drug Interactions: Anticonvulsants, lactulose, hormonal contraceptives.
- Pregnancy & Breastfeeding: Avoid use during pregnancy and exercise caution during breastfeeding.
- Dosage: Varies by indication and patient factors; see Dosage section above.
- Monitoring Parameters: Liver and kidney function, especially in patients with pre-existing conditions.
Popular Combinations
- Often combined with growth hormone and specialized nutritional support for short bowel syndrome. May be included as part of parenteral nutrition regimens.
Precautions
- General Precautions: Evaluate kidney and liver function, screen for allergies and metabolic disorders.
- Specific Populations: See Dosage section for details on adjustments for pregnant/breastfeeding women, children, elderly, and other special populations.
- Lifestyle Considerations: Limit alcohol to ensure maximum absorption and avoid unwanted side effects. Avoid driving if dizziness occurs.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for L-Glutamine?
A: Dosage varies depending on the indication and patient-specific factors. See the detailed Dosage section above.
Q2: What are the common side effects of L-Glutamine?
A: Common side effects include constipation, nausea, headache, and abdominal pain.
Q3: Is L-Glutamine safe during pregnancy?
A: There is not enough reliable information available regarding its medicinal use during pregnancy. It is best to avoid use.
Q4: How does L-Glutamine work in sickle cell disease?
A: It helps reduce oxidative stress, a key factor in the pathophysiology of sickle cell disease. It acts as a precursor for glutathione, a potent antioxidant.
Q5: Can L-Glutamine interact with other medications?
A: Yes, it can interact with anticonvulsants, lactulose, and hormonal contraceptives, among others. See Drug Interactions section.
Q6: Are there any contraindications for L-Glutamine use?
A: Yes, contraindications include hypersensitivity, severe liver or kidney disease, and Reye’s syndrome.
Q7: What is the role of L-Glutamine in gut health?
A: It serves as a primary energy source for intestinal cells, promoting their growth, repair, and function. It also supports the integrity of the intestinal barrier.
Q8: How should L-Glutamine powder be administered?
A: Mix the powder with cold or room temperature beverages (8 oz) or soft foods (4-6 oz) before ingestion. Complete dissolution is not required.
Q9: What should patients be advised regarding missed doses?
A: Patients should take a missed dose as soon as they remember. They should not double the dose.
