L-valine

Dosage for valine is highly individualized and depends on the patient's body weight, clinical condition, and whether it is being used for general nutritional support or therapeutic intervention.

• Parenteral Nutrition (TPN): In standard adult amino acid infusions, the total amino acid dose typically ranges from 0.8 to 1.5 grams per kilogram of body weight per day. Valine usually constitutes approximately 5% to 7% of these formulations. For a 70 kg adult, this equates to roughly 3.5 to 5.5 grams of valine daily as part of a complete nutritional regimen.
• Hepatic Encephalopathy: Specialized oral or IV formulas may provide higher concentrations of BCAAs. Clinical studies have utilized BCAA doses ranging from 12 to 25 grams per day, with valine making up a significant portion of that total.
• General Dietary Supplementation: While not strictly regulated, common supplemental doses range from 2 to 5 grams daily, often taken in divided doses.

In pediatric patients, valine requirements are significantly higher per kilogram of body weight due to the demands of growth and development.

• Neonates and Infants: Amino acid requirements can range from 2.0 to 3.5 g/kg/day. Valine is a critical component of pediatric-specific infusions (e.g., TrophAmine) designed to mimic the amino acid profile of breast milk.
• Children (1-12 years): Dosing is adjusted based on age and metabolic rate, typically ranging from 1.0 to 2.0 g/kg/day of total amino acids.

Renal Impairment

Patients with chronic kidney disease (CKD) require careful monitoring of nitrogen intake. While valine is essential, excessive amino acid administration can lead to an accumulation of blood urea nitrogen (BUN). In patients not on dialysis, protein/amino acid intake may be restricted to 0.6–0.8 g/kg/day. For those on hemodialysis, requirements increase to 1.2–1.5 g/kg/day.

Hepatic Impairment

In patients with cirrhosis, valine is often preferred over aromatic amino acids. However, total nitrogen load must be balanced to prevent hyperammonemia. Healthcare providers may use BCAA-enriched formulas specifically for these patients.

Elderly Patients

Older adults may require slightly higher protein/amino acid intake to counteract age-related sarcopenia (muscle loss). However, baseline renal function must be assessed before initiating high-dose valine supplementation.

• Parenteral Administration: Valine infusions must be administered via a central or peripheral venous catheter by a trained healthcare professional. The rate of infusion is strictly controlled to prevent metabolic complications.
• Oral Supplementation: If taking oral valine, it is generally recommended to take it approximately 30 to 60 minutes before or after a meal. Taking it with a small amount of carbohydrate may enhance muscle uptake via insulin stimulation.
• Storage: IV solutions should be stored at room temperature (20°C to 25°C) and protected from light. Do not use if the solution is discolored or contains precipitates.

If you are receiving valine as part of a clinical nutrition program, your healthcare team will manage the schedule. If you are taking oral supplements and miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose. Do not double the dose to catch up.

Acute toxicity from valine is rare in healthy individuals. However, excessive intake can lead to:

• Azotemia: An accumulation of nitrogenous waste products in the blood.
• Metabolic Acidosis: Particularly in patients receiving IV infusions with high chloride content.
• Neurological Symptoms: High levels of BCAAs can interfere with the transport of other essential amino acids to the brain, potentially causing fatigue or coordination issues.

In the event of a suspected overdose, especially in a clinical setting, the infusion should be stopped immediately, and electrolytes/BUN should be monitored.

> Important: Follow your healthcare provider's dosing instructions. Do not adjust your dose without medical guidance.

When administered at standard nutritional doses, valine is generally well-tolerated. However, when used in high-dose therapeutic contexts or via rapid IV infusion, the following may occur:

• Gastrointestinal Distress: Nausea, bloating, and mild abdominal cramping are frequently reported with oral BCAA supplements. These symptoms usually subside as the body adjusts to the supplement.
• Headache: Some patients report mild tension-type headaches shortly after administration.
• Metabolic Changes: A transient increase in blood urea nitrogen (BUN) is common as the body processes the additional nitrogen load.

• Fatigue: Some users report a sense of lethargy, likely due to the competition between valine and tryptophan for brain entry, which can affect serotonin levels.
• Diarrhea: Osmotic effects of high-dose oral amino acids can lead to loose stools.
• Injection Site Reactions: For those receiving IV valine, redness, swelling, or phlebitis (vein inflammation) at the infusion site may occur.

• Hyperammonemia: In patients with underlying urea cycle disorders or severe liver dysfunction, valine can contribute to elevated ammonia levels, leading to confusion or lethargy.
• Metabolic Acidosis: Excessive administration of amino acid salts can shift the blood's pH, particularly in neonates or patients with renal failure.
• Allergic Reactions: While rare for the amino acid itself, patients may react to other components in the infusion solution, such as sulfites used as preservatives.

> Warning: Stop taking Valine and call your doctor immediately if you experience any of these.

• Anaphylaxis: Symptoms include hives, difficulty breathing, swelling of the face, lips, or tongue. This is usually a reaction to the IV formulation components rather than the valine itself.
• Severe Confusion or Encephalopathy: If you notice sudden changes in mental status, extreme drowsiness, or tremors, it may indicate a metabolic imbalance or hyperammonemia.
• Pulmonary Edema: Shortness of breath or a persistent cough, which may occur if IV fluids are administered too rapidly or if there is an underlying heart condition.
• Severe Renal Distress: Significant decrease in urine output or swelling in the ankles and feet, indicating the kidneys are struggling to process the nitrogen load.

Prolonged use of high-dose valine without balancing it with other amino acids (leucine and isoleucine) can lead to a 'BCAA imbalance.' This may result in reduced muscle protein synthesis efficiency and potential neurological changes due to chronic LAT1 transporter saturation. Long-term excessive nitrogen intake can also place chronic strain on the kidneys, potentially accelerating the progression of pre-existing renal disease.

There are currently no FDA black box warnings for Valine as an individual amino acid. However, amino acid infusions used in parenteral nutrition often carry warnings regarding the risk of 'Precipitates in the Vascular System,' particularly when mixed with calcium and phosphates, which can lead to life-threatening pulmonary vascular emboli.

Report any unusual symptoms to your healthcare provider.

Valine is a potent metabolic agent. It should only be used under medical supervision, especially when administered intravenously or in high doses. The primary safety concern involves the body's ability to process nitrogen. Patients with metabolic disorders must be screened before initiating therapy.

No FDA black box warnings for Valine.

• Maple Syrup Urine Disease (MSUD): This is an absolute contraindication. Patients with MSUD lack the enzyme complex (BCKDH) necessary to break down valine. Accumulation of valine and its keto-acid metabolites can cause severe neurological damage, coma, and death.
• Allergic Reactions: Some intravenous amino acid products contain sulfites, which can cause allergic-type reactions, including anaphylactic symptoms and life-threatening or less severe asthmatic episodes in susceptible individuals.
• Hepatotoxicity and Liver Function: While BCAAs like valine are often used to treat liver disease, excessive nitrogen can exacerbate hepatic encephalopathy if the liver cannot convert ammonia to urea efficiently.
• Nephrotoxicity: In patients with pre-existing renal insufficiency, the nitrogen load from valine can lead to azotemia. Careful monitoring of creatinine and BUN is mandatory.
• Fluid and Electrolyte Balance: IV administration of valine-containing solutions can lead to fluid overload and significant electrolyte imbalances (e.g., hyponatremia, hypokalemia).

Patients receiving clinical valine therapy require regular monitoring of:

• Blood Urea Nitrogen (BUN) and Creatinine: To assess renal handling of nitrogen.
• Serum Electrolytes: Sodium, potassium, magnesium, and phosphorus levels.
• Liver Function Tests (LFTs): Including bilirubin and alkaline phosphatase.
• Blood Glucose: Amino acids can influence insulin secretion and gluconeogenesis.
• Acid-Base Balance: Monitoring for signs of metabolic acidosis.

Valine is not known to cause significant sedation in healthy individuals. However, because it can influence neurotransmitter precursors, some patients may experience mild fatigue or changes in concentration. Use caution when driving until you know how valine affects you.

Alcohol consumption should be avoided or strictly limited when taking therapeutic doses of valine. Alcohol can interfere with amino acid metabolism in the liver and may worsen the gastrointestinal side effects of oral supplements. Furthermore, alcohol can exacerbate the dehydration that sometimes accompanies high protein/amino acid intake.

In a parenteral nutrition setting, valine and other amino acids should not be stopped abruptly. Doing so can cause 'rebound hypoglycemia' because the body has adjusted its insulin production to the continuous infusion of nutrients. The infusion rate should be tapered gradually under medical supervision.

> Important: Discuss all your medical conditions with your healthcare provider before starting Valine.

• None specifically for the molecule valine: However, it is contraindicated in patients with Maple Syrup Urine Disease (MSUD) due to the inability to metabolize the substance.

• Levodopa (L-Dopa): Valine competes with Levodopa for transport across the blood-brain barrier via the Large Neutral Amino Acid (LNAA) transporter. High levels of valine can significantly reduce the amount of Levodopa that reaches the brain, potentially decreasing its effectiveness in treating Parkinson’s disease. Patients taking Levodopa should avoid high-dose valine supplements or time their intake several hours apart.
• Antidiabetic Medications (Insulin, Sulfonylureas): Valine can stimulate insulin secretion and promote glucose uptake in muscle cells. When combined with insulin or oral hypoglycemic agents (e.g., metformin, glipizide), there is an increased risk of hypoglycemia (low blood sugar). Close monitoring of blood glucose is required.

• Corticosteroids: Drugs like prednisone can increase the breakdown of body proteins, potentially altering the requirements for valine and other amino acids.
• Thyroid Hormones: Changes in metabolic rate caused by thyroid medications can influence the rate at which the body utilizes valine for protein synthesis.

• High-Protein Meals: Consuming valine supplements with a high-protein meal can lead to competition for intestinal transporters, reducing the absorption efficiency of the supplement.
• Dairy Products: The high calcium and protein content in dairy can interfere with the absorption of pure valine supplements.

• Other BCAAs (Leucine and Isoleucine): While usually taken together, an extreme excess of one BCAA relative to the others can cause a metabolic imbalance. It is generally recommended to maintain a balanced ratio.
• 5-HTP and Tryptophan: Because valine competes with tryptophan for brain entry, taking high doses of valine may reduce the effectiveness of tryptophan or 5-HTP supplements used for sleep or mood.

• Blood Urea Nitrogen (BUN): Valine supplementation will naturally increase BUN levels. This is a physiological result of nitrogen metabolism and may not always indicate renal pathology, though it must be interpreted carefully by a physician.
• Serum Ammonia: In patients with liver dysfunction, valine may affect ammonia readings.
• Urinary Ketones: In rare cases, metabolites of valine can cause a false-positive result for ketones in the urine.

> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking.

• Maple Syrup Urine Disease (MSUD): This is the most critical contraindication. Valine is a branched-chain amino acid, and patients with MSUD lack the functional BCKDH enzyme complex to process its keto-acid derivative. Continued intake leads to toxic accumulation, causing cerebral edema, seizures, and permanent neurological impairment.
• Hypersensitivity: Any known allergy to valine or any component of the specific formulation (such as sulfites in IV solutions) is an absolute contraindication.
• Severe Inborn Errors of Amino Acid Metabolism: Beyond MSUD, other rare genetic disorders affecting the urea cycle or specific amino acid pathways may preclude the use of concentrated valine.

• Severe Renal Failure: In patients with a GFR < 15 mL/min who are not on dialysis, the nitrogen load from valine may be dangerous. The risk of uremia must be weighed against the need for nutritional support.
• Advanced Cirrhosis with Hyperammonemia: While BCAAs are often used for liver disease, if the patient is in an acute state of ammonia toxicity, any additional nitrogen source must be introduced with extreme caution.
• Congestive Heart Failure (CHF): For IV valine, the fluid volume required for administration may exacerbate heart failure or pulmonary edema.

Patients who have had allergic reactions to other amino acid infusions or specific protein sources (like soy or egg, if used in the lipid portion of a TPN mixture) should be monitored closely, although valine itself is a naturally occurring human nutrient and rarely causes cross-sensitivity on its own.

> Important: Your healthcare provider will evaluate your complete medical history before prescribing Valine.

Valine is a naturally occurring essential amino acid and is a normal component of the human diet. During pregnancy, amino acid requirements increase to support fetal growth. According to the FDA, amino acids are generally considered safe during pregnancy when used as part of a balanced nutritional program. However, high-dose 'pharmacological' supplementation of valine has not been extensively studied in pregnant women. It should only be used if the potential benefit justifies the potential risk to the fetus. There is no evidence of teratogenicity at physiological doses.

Valine is a natural constituent of human breast milk. Supplemental valine taken by the mother is likely to increase the concentration in milk, but this is generally considered safe for the nursing infant, as valine is essential for infant growth. However, nursing mothers should consult a physician before taking high-dose isolated amino acid supplements.

Valine is essential for pediatric growth. In clinical settings, it is a standard component of pediatric parenteral nutrition. The dosage must be carefully calculated based on the child's weight and developmental stage. It is NOT approved for use in children with Maple Syrup Urine Disease. Monitoring for metabolic acidosis and hyperammonemia is particularly important in neonates due to their immature metabolic pathways.

Clinical studies suggest that elderly patients may have a higher requirement for BCAAs like valine to prevent sarcopenia (muscle wasting). However, geriatric patients are also more likely to have reduced renal clearance. Healthcare providers typically start with lower doses and monitor renal function (BUN and Creatinine) closely. There is no specific evidence that valine increases fall risk, but metabolic imbalances in the elderly can lead to confusion.

In patients with impaired kidney function, the metabolic byproducts of valine (urea and other nitrogenous wastes) can accumulate. For patients with a GFR between 15-60 mL/min, protein intake is often moderated. For those on dialysis, valine is often supplemented because it is easily cleared during the dialysis procedure, leading to potential deficiency.

Valine is often used therapeutically in patients with Child-Pugh Class B or C cirrhosis. Because BCAAs are metabolized primarily in the muscle rather than the liver, they provide an energy source that doesn't tax the liver. However, if the patient has reached the stage of hepatorenal syndrome, the renal considerations mentioned above take precedence.

> Important: Special populations require individualized medical assessment.

Valine is an essential branched-chain amino acid (BCAA) with an aliphatic side chain. Its primary molecular role is as a substrate for protein synthesis. Once transported into the cell via the LAT1 or B0AT1 transporters, it is charged onto tRNA molecules by valyl-tRNA synthetase for incorporation into nascent protein chains.

Beyond protein synthesis, valine serves as a precursor for the synthesis of other metabolites. Its oxidative catabolism begins with transamination to alpha-ketoisovalerate (KIV). KIV is then decarboxylated by the BCKDH complex. This pathway eventually yields succinyl-CoA, which enters the Citric Acid Cycle, making valine a 'glucogenic' amino acid. This allows it to support blood glucose levels during periods of metabolic stress.

The pharmacodynamic effect of valine is primarily nutritional and metabolic. It helps maintain a positive nitrogen balance, which is essential for wound healing and muscle preservation. In the central nervous system, valine competes for transport with aromatic amino acids, thereby modulating the levels of serotonin and catecholamines. This competitive inhibition is the basis for its use in treating hepatic encephalopathy.

| Parameter | Value |

|---|---|

| Bioavailability | >90% (Oral) |

| Protein Binding | Negligible (circulates as free amino acid) |

| Half-life | 2 - 4 hours |

| Tmax | 0.5 - 1.5 hours (Oral) |

| Metabolism | Skeletal Muscle (BCKDH complex) |

| Excretion | Renal (<5% as unchanged drug) |

• Molecular Formula: C5H11NO2
• Molecular Weight: 117.15 g/mol
• Solubility: Soluble in water (8.85 g/100 mL at 25°C); slightly soluble in alcohol.
• Structure: Valine contains an alpha-amino group, an alpha-carboxylic acid group, and an isopropyl side chain, making it a non-polar, hydrophobic amino acid.

Valine is classified as a Branched-Chain Amino Acid (BCAA) and is part of the broader Amino Acid [EPC] therapeutic class. It is often grouped with Leucine and Isoleucine due to their similar chemical structures and shared metabolic pathways.