Irigate

Glycine is an amino acid used therapeutically for several medical and nutritional purposes.

Approved Indications:

• Adjunct in certain metabolic disorders: Used to support metabolic balance in patients with amino acid deficiencies.
• Neuroprotective support: Investigated in clinical settings for neurological disorders, including schizophrenia and stroke recovery, to improve cognitive function.
• Sleep and sedation support: Utilized as a mild sedative for improving sleep quality.
• Nutritional supplementation: Used in patients with malnutrition, hepatic impairment, or increased metabolic demands.

Clinically Accepted Off-Label Uses:

• Treatment of non-ketotic hyperglycinemia as part of dietary and pharmacologic management.
• Supportive therapy in muscle wasting or sarcopenia.
• Adjunct in psychiatric or neurological disorders, including mood and cognitive impairments.

Adults:

• Oral supplementation: 1–3 g/day in divided doses, depending on indication.
• Intravenous use: 0.1–0.5 g/kg/day for metabolic support or specific clinical applications.

Elderly:

• Same as adult dose; monitor renal function for IV administration.

Pediatrics:

• Dose adjusted according to body weight and clinical need; typically 50–150 mg/kg/day.

Special Populations:

• Renal impairment: Dose adjustment required; monitor for accumulation.
• Hepatic impairment: Usually well-tolerated; monitor liver function if high doses are used.

Administration Notes:

• Oral glycine is typically taken with meals to improve absorption.
• IV glycine should be administered under clinical supervision to monitor for fluid overload or electrolyte disturbances.

Glycine is a non-essential amino acid that functions as an inhibitory neurotransmitter in the central nervous system, primarily in the spinal cord and brainstem. By binding to glycine receptors, it enhances chloride influx into neurons, producing hyperpolarization and inhibitory effects that modulate neuronal excitability. Glycine also acts as a co-agonist at NMDA receptors, enhancing glutamatergic neurotransmission, which is important for cognitive and neuroprotective effects. Additionally, glycine contributes to protein synthesis, detoxification pathways, and antioxidant defense, providing systemic metabolic support.

• Absorption: Rapidly absorbed after oral administration; bioavailability ~70–90%.
• Distribution: Widely distributed in body tissues, particularly in CNS and muscle; low plasma protein binding.
• Metabolism: Metabolized primarily in liver and kidney; participates in one-carbon metabolism and creatine synthesis.
• Excretion: Eliminated mainly via urine as glycine and its metabolites.
• Half-life: Approximately 0.5–1 hour after oral administration; longer with IV infusion due to saturation kinetics.
• Onset of Action: Effects on neurotransmission occur within 30–60 minutes orally; metabolic effects accumulate over days.

• Pregnancy: Generally regarded as safe; no evidence of teratogenicity in humans. Used as a nutritional supplement.
• Lactation: Safe when used at standard dietary doses; excreted in breast milk in small amounts without known adverse effects.
• Note: High pharmacologic doses should be used cautiously during pregnancy and lactation.

• Primary Class: Amino acid / Nutritional supplement
• Subclass: Neurotransmitter modulator / metabolic support agent

• Known hypersensitivity to glycine or excipients.
• Severe renal failure (for IV administration without monitoring).
• Caution in patients with inborn errors of glycine metabolism unless clinically indicated.

• High-risk patients:
• Renal impairment — monitor for accumulation.
• Hepatic dysfunction — monitor liver enzymes if high doses used.
• Serious potential risks: Rare IV overdosage may lead to hyperosmolarity, nausea, vomiting, or hypotension.
• Monitoring: Clinical monitoring of renal and hepatic function recommended for prolonged high-dose therapy.
• Early signs of severe adverse events: Nausea, vomiting, hypotension, CNS depression — discontinue or adjust dose.

Common:

• Mild gastrointestinal discomfort (nausea, bloating)
• Soft stools or diarrhea
• Drowsiness at higher doses

Serious/Rare:

• Hypotension (mainly with rapid IV infusion)
• CNS depression or dizziness
• Electrolyte imbalance with prolonged high-dose IV therapy

Dose Dependence: Side effects generally mild at standard doses and increase with higher or rapid IV dosing.

• Drug-Drug:
• May potentiate sedative effects of CNS depressants (benzodiazepines, alcohol).
• Interacts with drugs influencing NMDA receptor function.
• Drug-Food: No significant interactions noted.
• Drug-Alcohol: Alcohol may increase CNS depressant effects.
• Enzyme Systems: Glycine does not significantly affect CYP450 metabolism.

• Glycine supplementation is increasingly studied for sleep disorders, metabolic support in critical illness, and neurological protection.
• Recent guidelines in metabolic disorders recommend glycine as an adjunct in non-ketotic hyperglycinemia management.
• Evidence supports cognitive benefits in schizophrenia as part of adjunct therapy with antipsychotics.

• Store at 20°C–25°C (room temperature).
• Protect from light, moisture, and heat.
• Keep in a tightly closed container.
• Do not freeze.
• Keep out of reach of children.