Drug reference

fluorexon

Ophthalmic diagnostic dye (high-molecular-weight fluorescein analog) · Diagnostic agent

START

1–2 drops of 0.35% solution to conjunctival sac

TYPICAL MAX

1–2 drops per examination

STOP IF

Hypersensitivity reaction

WATCH

Limited corneal staining (different from fluorescein); avoid in fluorescein-anaphylaxis history

CDSCO approvedATC S01JA02

Dose laddermg/d

Renal dose adjustmenteGFR mL/min/1.73m²

KDIGO 2024 + manufacturer label

Pharmacokineticsplasma · t hours

ONSET: 18s · seconds
PEAK: 3min · local peak
t½: 30min · lacrimal
DURATION: 6min · few min

EXCRETION

Local lacrimal clearance

route + CYP

INTERACTIONS

—

none in our sources

PREGNANCY

Topical ocular use — minimal systemic exposure; safe.

FDA category + note

Mechanism

Calcein/fluorexon (calcium-chelating fluorescein derivative) — fluorescent under blue light but with limited corneal staining of intact epithelium; used to evaluate hydrogel contact-lens fit and surface integrity without staining the lens itself (unlike fluorescein).

Indications

Soft contact-lens fitting assessmentOphthalmic diagnostic procedures where standard fluorescein would stain lenses

Dosing

Adult: 1–2 drops of 0.35% solution to the conjunctival sac as needed for examination.
Pediatric: Same as adult.
Renal adjustment: No adjustment.
Hepatic adjustment: No adjustment.
Geriatric: No specific adjustment.
Max dose: 1–2 drops per examination

Pharmacokinetics

Onset

Fluorescence within seconds

Peak effect

Local (immediate)

Duration

Local clearance over minutes

Half-life

Not applicable (topical; negligible systemic)

Bioavailability

Negligible systemic

Protein binding

Not relevant

Metabolism

Negligible systemic metabolism

Excretion

Local lacrimal clearance

Contraindications

Severe hypersensitivity
Caution: prior fluorescein-derivative anaphylaxis

Side effects

Common

Transient yellow-green ocular discolourationMild stinging on instillationReflex tearing

Serious

Severe hypersensitivity (very rare)

Pregnancy & lactation

Pregnancy

Topical ocular use — minimal systemic exposure; safe.

Lactation

Compatible (negligible systemic).

Drug interactions

Beta Blockers

Mild

Database

May blunt anaphylaxis treatment (theoretical)

Standard topical safety