Fluorescein sodium is a diagnostic dye used primarily in ophthalmology. The 20% concentration is a sterile, injectable solution for intravenous administration. It is a fluorescent compound that, when excited by blue light (wavelength 465-490 nm), emits a yellow-green fluorescence (520-530 nm). This property allows for the visualization of blood flow and the detection of vascular abnormalities in the retina and choroid, as well as corneal epithelial defects. It is a cornerstone of diagnostic retinal imaging.
Adult: 500 mg (2.5 mL of 20% solution) administered as a rapid intravenous bolus injection into a large antecubital vein. Typical dose range is 500-750 mg (2.5-3.75 mL).
Note: 1. Use a sterile 3-5 mL syringe with a 20-23 gauge needle. 2. Ensure IV access is secure to prevent extravasation. 3. Inject rapidly as a bolus (over 2-5 seconds) followed by a saline flush. 4. Angiography imaging sequences begin immediately after injection. 5. Patient should be in a seated or reclined position for the procedure. 6. Resuscitation equipment (adrenaline, antihistamines, oxygen) must be immediately available.
Fluorescein sodium is a small, water-soluble molecule that diffuses freely through most capillaries but not through the tight junctions of the retinal vascular endothelium (blood-retinal barrier). When injected intravenously, it circulates with the blood. Under blue excitation light, it emits yellow-green fluorescence, allowing real-time visualization of the retinal and choroidal circulation. Leakage, pooling, or staining patterns indicate breakdown of vascular integrity or barriers.
Pregnancy: Pregnancy Category C (US FDA). Animal reproduction studies have not been conducted. It is not known whether fluorescein can cause fetal harm. Use only if clearly needed, such as when retinal disease threatens the mother's vision. It does cross the placenta.
Driving: Patients should be advised not to drive immediately after the procedure due to potential for dizziness, syncope, or transient visual disturbances from bright photographic flashes. They may resume once all effects have subsided.
| Probenecid | May competitively inhibit renal tubular secretion of fluorescein, potentially prolonging its half-life and increasing plasma levels. | Moderate |
| Other diagnostic dyes (e.g., Indocyanine Green - ICG) | If administered concurrently, may interfere with fluorescence imaging. Sequential administration with a waiting period is standard. | Moderate |
Same composition (Fluorescein (20%)), different brands: