L-Histidine Hydrochloride + L-Isoleucine + L-Leucine + Phenylalanine

Usage

This combination of amino acids is primarily used as a nutritional supplement to address protein deficiencies in individuals unable to obtain sufficient amounts through their diet. It’s indicated for conditions like malnutrition, malabsorption syndromes, or in patients receiving parenteral nutrition. It supports various metabolic processes, including protein synthesis, tissue repair, and hormone production. This mixture doesn’t belong to a single pharmacological class but is considered a nutritional supplement. The mechanism of action involves supplying the body with essential amino acids required for protein synthesis and other metabolic functions. Histidine contributes to tissue growth and repair. Isoleucine and leucine are important for muscle metabolism, while phenylalanine serves as a precursor for neurotransmitters.

Alternate Names

This specific combination lacks a distinct international nonproprietary name (INN). It’s typically identified by its component amino acids: L-Histidine hydrochloride, L-Isoleucine, L-Leucine, and Phenylalanine. There are no widely recognized brand names for this particular combination. Formulations containing these amino acids, often with additional components, are marketed under various brand names depending on the manufacturer and specific formulation.

How It Works

Pharmacodynamics: These essential amino acids are crucial for protein synthesis, hormone and neurotransmitter production, and nitrogen balance. They contribute to cell growth, repair, and various metabolic processes.

Pharmacokinetics:

• Absorption: When administered intravenously, bioavailability is 100%. Oral absorption varies for each amino acid, but generally, they are absorbed well in the small intestine.
• Metabolism: Each amino acid has specific metabolic pathways. Phenylalanine is converted to tyrosine, which is a precursor for dopamine, norepinephrine, and epinephrine. The branched-chain amino acids (Leucine, Isoleucine, and Valine) are primarily metabolized in muscle tissue.
• Elimination: Primarily through renal excretion.

Dosage

Dosage is individualized and depends on the patient’s specific needs, metabolic state, and clinical condition.

Standard Dosage

Adults: 1.5 - 3.5 g of amino acids/kg/24 hours intravenously. This should be administered via a central venous catheter with the tip positioned in the central vena cava.

Children: Dosing is weight-based, similar to adults (1.5-3.5g amino acids/kg/24 hours). Pediatric patients require careful dosing calculations based on their age, weight, and metabolic requirements. For neonates or premature infants, administer by continuous infusion or in cycles (over 12-24 hours), with an infusion rate not exceeding 0.05 ml/kg/minute. Consult specialized pediatric dosing guidelines. Monitor blood ammonia levels in newborns and infants closely for early detection of hyperammonemia.

Special Cases:

• Elderly Patients: Dosage adjustment may be necessary based on renal and hepatic function.
• Patients with Renal Impairment: Dose reduction is needed based on the degree of impairment.
• Patients with Hepatic Dysfunction: Careful monitoring of blood ammonia and liver function is essential. Dose adjustment might be necessary.
• Patients with Comorbid Conditions: Consider individual conditions (e.g., diabetes, cardiovascular disease) and adjust dosage accordingly.

Clinical Use Cases

Dosage is tailored to individual needs in various clinical settings such as post-surgical recovery, critical illness, burns, and during mechanical ventilation or in the ICU. Specific guidelines apply to these situations.

Dosage Adjustments

Modifications are necessary based on patient factors like renal/hepatic function, metabolic disorders, or genetic polymorphisms. Close monitoring of electrolytes, blood ammonia, and liver function tests is essential.

Side Effects

Common Side Effects

Generally, this combination is well-tolerated. Some patients might experience mild gastrointestinal discomfort such as nausea, vomiting, or diarrhea.

Rare but Serious Side Effects

Allergic reactions (rash, itching, swelling), hyperammonemia (especially with pre-existing liver disease), and metabolic acidosis (with rapid or high-dose administration) can occur.

Long-Term Effects

Limited data exist regarding long-term effects. Regular monitoring of organ function and nutritional status is essential during prolonged use.

Adverse Drug Reactions (ADR)

Severe hypersensitivity reactions (anaphylaxis) and electrolyte imbalances can occur.

Contraindications

• Hypersensitivity to any of the amino acids in the formulation.
• Severe hepatic or renal impairment.
• Inborn errors of amino acid metabolism (e.g., phenylketonuria).

Drug Interactions

Limited data are available. Potential interactions with certain medications (e.g., some antihypertensives, antidiabetics, antibiotics) should be considered. Concurrent use of certain other medications warrants close monitoring. Alcohol should be avoided while taking this medication.

Pregnancy and Breastfeeding

Caution is advised due to limited safety data. Physician consultation is necessary before use.

Drug Profile Summary

• Mechanism of Action: Provides essential amino acids for protein synthesis and various metabolic processes.
• Side Effects: Generally well-tolerated, rare gastrointestinal issues or allergic reactions.
• Contraindications: Hypersensitivity, severe hepatic/renal impairment, inborn errors of metabolism.
• Drug Interactions: Potential interactions with certain medications, avoid alcohol.
• Pregnancy & Breastfeeding: Use with caution and consult a physician.
• Dosage: Individualized based on patient needs; 1.5-3.5g/kg/24h IV for adults and children.
• Monitoring Parameters: Electrolytes, blood ammonia, liver function tests.

Popular Combinations

This amino acid combination is often included in parenteral nutrition solutions alongside dextrose, electrolytes, vitamins, and trace elements.

Precautions

Screen for allergies, metabolic disorders, and organ dysfunction. Take precautions in pregnant/breastfeeding women, children, the elderly, and individuals with specific medical conditions. Advise on lifestyle factors like alcohol avoidance.

FAQs (Frequently Asked Questions)

Q1: What is the standard dosage of this amino acid combination?

A: The usual dosage range is 1.5 - 3.5 g of amino acids/kg/24 hours intravenously, adjusted according to individual needs.

Q2: How is this combination administered?

A: It’s administered intravenously, typically through a central venous catheter.

Q3: What are the common side effects?

A: Common side effects are generally mild and may include nausea, vomiting, or diarrhea.

Q4: Are there any serious side effects?

A: Yes, rare but serious side effects include allergic reactions, hyperammonemia, and metabolic acidosis.

Q5: Can this combination be used in patients with liver disease?

A: It should be used with extreme caution in patients with liver disease due to the risk of hyperammonemia. Close monitoring of liver function and blood ammonia levels is critical.

Q6: Is this combination safe during pregnancy?

A: Limited safety data exist for pregnancy. Consult a physician before use.

Q7: Can this combination be used in children?

A: Yes, but dosage must be calculated based on the child’s weight and metabolic needs. Pediatric dosage guidelines should be followed.

Q8: What monitoring parameters are essential during therapy?

A: Monitor electrolytes, blood ammonia, and liver function tests.

Q9: What should be done if a patient experiences an allergic reaction?

A: Discontinue the infusion immediately and provide appropriate medical management for allergic reactions.

Q10: Can this mixture be used in patients with renal impairment?

A: It should be used with caution and dose adjustments are necessary in patients with renal impairment.