Usage
Ornithine is primarily used in the management of hepatic encephalopathy, a condition characterized by impaired brain function due to liver disease. It helps reduce elevated ammonia levels in the blood, a key factor contributing to hepatic encephalopathy. While studied for potential benefits in athletic performance, wound healing, and other areas, robust scientific evidence for these uses is lacking. It is classified as a hepatoprotective agent and an ammonia-lowering agent. It works by participating in the urea cycle, facilitating ammonia detoxification in the liver. It also plays a role in the Krebs cycle contributing to energy production.
Alternate Names
This amino acid is often referred to as L-ornithine. There aren’t widely recognized international variations for L-ornithine itself; however, combinations like L-ornithine-L-aspartate (LOLA) and ornithine alpha-ketoglutarate (OKG) exist. While they contain ornithine, they are distinct compounds. Brand names vary by region; one example is Hepa-Merz.
How It Works
Pharmacodynamics: Ornithine’s primary effect is reducing elevated blood ammonia levels. It achieves this through two main mechanisms. First, it acts as a substrate in the urea cycle, the metabolic pathway responsible for converting ammonia to urea, which is then excreted by the kidneys. Second, it can be transformed into glutamate, another amino acid, consuming ammonia in the process. The reduction in ammonia levels helps alleviate the symptoms of hepatic encephalopathy.
Pharmacokinetics: Ornithine is administered intravenously or orally. Oral administration is generally well-tolerated. Data on its specific absorption, distribution, and metabolism when given as ornithine hydrochloride is limited. After conversion to glutamate, it is involved in other metabolic processes. Elimination details are not comprehensively documented; it likely involves metabolism. LOLA is administered intravenously and rapidly dissociates into ornithine and aspartate after administration.
Mode of Action: Ornithine’s mode of action revolves around ammonia detoxification primarily through the urea cycle, a sequence of biochemical reactions within the liver.
Dosage
Standard Dosage
Adults:
Oral L-Ornithine L-Aspartate: 1-2 sachets or 1-2 tablets three times daily. Intravenous L-Ornithine L-Aspartate: Up to 20g daily (up to 4 ampoules), 5g/hr maximum infusion rate. In hepatic encephalopathy (pre-coma or coma), up to 8 ampoules can be administered within 24 hours. Ornithine hydrochloride: intravenous dose 20-40 g in combination with aspartate.
Children:
Pediatric dosing recommendations are not well-established for all forms of ornithine. For acute pediatric hyperammonemia, L-Ornithine-L-aspartate may be considered at an initial dose of 200 mg/kg via nasogastric tube, followed by 200 mg/kg every 3-6 hours. Consultation with a metabolic specialist is crucial. Safety and efficacy in children are not fully established.
Special Cases:
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Elderly Patients: No specific dosage adjustments based on age are universally recommended, but close monitoring is advisable due to potential age-related changes in organ function.
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Patients with Renal Impairment: In severe renal impairment or renal failure, L-Ornithine L-Aspartate is contraindicated.
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Patients with Hepatic Dysfunction: Dosage adjustments are not routinely provided for hepatic dysfunction itself, as the primary indication for ornithine is hepatic encephalopathy.
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Patients with Comorbid Conditions: Exercise caution in patients with severe renal impairment.
Clinical Use Cases
Dosage in these settings requires individualized assessment and specialist consultation:
- Intubation: Data specific to intubation is not explicitly available.
- Surgical Procedures: Dosage adjustments are not explicitly specified for surgical procedures.
- Mechanical Ventilation: Data specific to mechanical ventilation is not explicitly available.
- Intensive Care Unit (ICU) Use: Dosing should be determined based on individual patient needs and condition.
- Emergency Situations: Consult a metabolic specialist in emergencies related to hyperammonemia.
Dosage Adjustments
Closely monitor patients with renal impairment. No specific dose adjustments are explicitly outlined for other conditions. Therapeutic drug monitoring of ammonia levels is critical.
Side Effects
Common Side Effects
Nausea, vomiting and stomach or intestinal discomfort.
Rare but Serious Side Effects
No serious adverse reactions have been directly linked to ornithine. However, rapid infusion can cause discomfort.
Long-Term Effects
Information regarding long-term adverse effects of ornithine is limited.
Adverse Drug Reactions (ADR)
No severe ADRs specifically related to ornithine are commonly reported.
Contraindications
Hypersensitivity to ornithine, severe renal failure.
Drug Interactions
No clinically significant drug interactions with ornithine are well-documented.
Pregnancy and Breastfeeding
Insufficient data exists to determine the safety of ornithine during pregnancy and breastfeeding. Avoid use unless deemed essential by a healthcare professional.
Drug Profile Summary
- Mechanism of Action: Facilitates ammonia detoxification through the urea cycle. Promotes glutamate synthesis.
- Side Effects: Nausea, vomiting.
- Contraindications: Hypersensitivity to ornithine, severe renal failure.
- Drug Interactions: Not well-documented.
- Pregnancy & Breastfeeding: Insufficient data to ensure safety.
- Dosage: Varies by formulation and indication.
- Monitoring Parameters: Ammonia levels, renal function tests, liver function tests
Popular Combinations
L-Ornithine-L-Aspartate is the most commonly encountered combination.
Precautions
Monitor patients with renal impairment. Closely monitor patients in all settings.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Ornithine?
A: Dosing varies based on the formulation (L-ornithine-L-aspartate, ornithine alpha-ketoglutarate, ornithine hydrochloride), route of administration (oral, intravenous), and indication. Consult appropriate guidelines for specific cases.
Q2: What is the primary use of ornithine in clinical practice?
A: Hepatic encephalopathy.
Q3: How does ornithine lower ammonia levels?
A: It participates in the urea cycle, converting ammonia to urea. It also contributes to glutamate synthesis.
Q4: Is ornithine safe during pregnancy?
A: Safety during pregnancy hasn’t been definitively established. Avoid use unless benefits outweigh risks.
Q5: What are the common side effects of ornithine?
A: Nausea and vomiting are the most frequently reported side effects.
Q6: Are there any drug interactions with ornithine?
A: Clinically significant drug interactions are not well-documented.
Q7: What monitoring is necessary for patients on ornithine?
A: Ammonia levels should be monitored regularly. Liver and renal function tests are also important.
A: Yes, L-ornithine-L-aspartate, ornithine alpha-ketoglutarate, and ornithine hydrochloride exist, each with distinct properties.
Q9: Can ornithine be used in patients with renal impairment?
A: L-Ornithine L-Aspartate is contraindicated in severe renal impairment or renal failure. Caution is advised in milder cases.
Q10: What is the role of ornithine in the urea cycle?
A: It acts as a substrate, contributing to the conversion of ammonia into urea.
