1. Clinical Overview
Glycine 1.5% w/v is an irrigation solution, primarily a 1.5% solution of the amino acid glycine in sterile water for injection. It is a non-electrolytic, non-hemolytic, and low-viscosity fluid used as an irrigating medium during urological endoscopic procedures, particularly transurethral resection of the prostate (TURP) and other transurethral resections. It provides a clear visual field, is non-conductive, and is rapidly absorbed and metabolized, minimizing the risk of hemolysis compared to water.
| Onset | Duration | Bioavailability |
|---|---|---|
| Immediate upon instillation as an irrigant. | Duration is limited to the time of surgical irrigation; systemic effects depend on absorption volume and rate. | Not applicable in the conventional sense. Systemic bioavailability following irrigation is variable and depends on the volume absorbed through open prostatic veins and sinuses. |
2. Mechanism of Action
As an irrigant, it distends the operative field, washes away blood and debris, and provides a clear visual field during endoscopic surgery. Its low viscosity and non-conductive nature make it ideal for use with monopolar electrocautery. When absorbed systemically, glycine acts as an inhibitory neurotransmitter in the central nervous system (CNS) and spinal cord, competing with glutamate. This can lead to CNS depression and visual disturbances. It also contributes to an osmotic diuresis and can cause hyperammonemia in susceptible individuals.
3. Indications & Uses
- Irrigation solution for use during transurethral resection of the prostate (TURP)
- Irrigation solution for use during transurethral resection of bladder tumors (TURBT)
- Irrigation in other endoscopic urological procedures requiring a non-conductive, clear fluid medium
4. Dosage & Administration
Adult Dosage: Not a dosage in mg/kg. Used as a continuous irrigation fluid during surgery. The volume used is the minimum necessary to maintain a clear visual field, typically ranging from 10 to 30 liters per procedure, with careful monitoring for systemic absorption.
Administration: For sterile irrigation only. NOT FOR INJECTION. Use with appropriate urological irrigation system (e.g., Iglesias continuous flow resectoscope). Container is connected via sterile tubing. Irrigation pressure should be kept as low as possible (typically 60-80 cm H2O) to minimize intravasation. Use under strict aseptic conditions. Solution should be at room temperature or warmed to body temperature to prevent hypothermia.
5. Side Effects
Common side effects may include:
- Transient visual disturbances (blurred vision, temporary blindness)
- Nausea and vomiting
- Headache
- Mild hypotension or hypertension
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Other Irrigation Fluids (e.g., Mannitol, Sorbitol) | Additive risk of fluid and electrolyte shifts if switched or mixed. | Moderate |
| Diuretics (e.g., Furosemide) | May be used therapeutically to treat fluid overload from absorption, but requires careful monitoring of electrolytes. | Moderate |
| Anesthetics (especially Spinal/Epidural) | Hyponatremia can potentiate the effects of local anesthetics and increase neurological risk. | Major |
| Drugs causing SIADH (e.g., SSRIs, Carbamazepine) | Increased risk of severe hyponatremia. | Major |
7. Patient Counselling
- Do report any history of kidney, liver, or heart disease to your surgeon before the procedure.
- Do understand that temporary visual changes are a known possible side effect.
- Don't drive or operate machinery for at least 24 hours after the procedure or until your vision and alertness are completely normal.
- Don't hesitate to report severe headache, nausea, vomiting, or confusion after the procedure.
8. Toxicology & Storage
Overdose: Manifests as 'TURP Syndrome' or Glycine Toxicity: Hyponatremia (Na+ <125 mEq/L), nausea, vomiting, visual disturbances (blurred vision, transient blindness), confusion, seizures, bradycardia, hypertension followed by hypotension, pulmonary edema, coma, and potentially death.
Storage: Store at room temperature (between 15°C to 30°C). Protect from freezing and excessive heat. Do not use if the container is damaged, leaking, or if the solution is cloudy or contains particles. Keep out of reach of children. Single-use only. Discard any unused portion.