ISOPAQUE 440

Clinical safety rating: caution

Comprehensive clinical and safety monograph for ISOPAQUE 440 (ISOPAQUE 440).

How it works

Iodinated radiocontrast agent that attenuates X-rays by increasing the iodine content in tissues, providing enhanced visualization of vasculature and organs during imaging procedures.

What the body does with it

Metabolism	Not metabolized; excreted unchanged via glomerular filtration with minimal tubular reabsorption.
Excretion	Primarily renal excretion via glomerular filtration. Approximately 95% of the administered dose is excreted unchanged in the urine within 24 hours. Less than 5% is eliminated via biliary/fecal routes.
Half-life	Terminal elimination half-life is approximately 1.5 to 2 hours in patients with normal renal function. May be prolonged in renal impairment, correlating with creatinine clearance; dose adjustment not typically required for diagnostic procedures.
Protein binding	Low protein binding: approximately 5% bound to plasma proteins, mainly albumin.
Volume of Distribution	Volume of distribution is approximately 0.2–0.3 L/kg, consistent with distribution primarily in extracellular fluid. Indicates minimal tissue penetration, remaining largely intravascular/extracellular.
Bioavailability	Not applicable for oral administration; administered intravenously or intra-arterially. Bioavailability is 100% via intravascular routes.
Onset of Action	Intravenous administration: immediate (within seconds) for contrast enhancement during imaging. Intra-arterial: immediate as bolus reaches target vessels. No oral administration; strictly parenteral.
Duration of Action	Duration of contrast enhancement is approximately 5–10 minutes for dynamic studies (CT, angiography), with rapid redistribution and elimination. Functional imaging window may extend up to 30 minutes but diminishes quickly.

Classification & Brands

Dosing & administration

Intravenous: 50-100 mL (22.05-44.1 g iodine) as a single dose for CT imaging; intra-arterial: 5-80 mL (2.2-35.28 g iodine) depending on procedure; dose is based on imaging requirements and patient weight.

Dosage form	INJECTABLE
Renal impairment	eGFR <30 mL/min/1.73m²: avoid use; eGFR 30-45: use lowest necessary dose, ensure adequate hydration, and consider stopping metformin 48h before; no specific dose reduction formula.
Liver impairment	No dose adjustment recommended for hepatic impairment; caution in severe disease due to potential coagulation abnormalities.
Pediatric use	Weight-based: 1.0-2.0 mL/kg (0.44-0.88 g iodine/kg) for CT; maximum single dose not to exceed 4.0 mL/kg (1.76 g iodine/kg); adjust for body size and imaging indication.
Geriatric use	No specific dose adjustment; consider age-related renal function decline; use lowest effective dose, ensure adequate hydration, and monitor renal function before and after administration.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for ISOPAQUE 440 (ISOPAQUE 440).

Breastfeeding	Minimal excretion into breast milk. M/P ratio not established for metrizoate. Iodinated contrast agents are considered compatible with breastfeeding; however, a 12-24 hour interruption of breastfeeding may be considered to minimize infant exposure to free iodide.
Teratogenic Risk	Isopaque 440 (metrizoate) is an ionic iodinated contrast agent. Fetal risks: First trimester - theoretical risk of fetal thyroid dysfunction from iodine exposure; however, limited human data show no consistent teratogenicity. Second and third trimesters - potential for neonatal hypothyroidism if used near term due to fetal thyroid uptake of free iodide. The drug crosses the placenta.

Warnings & precautions

■ FDA Black Box Warning

None identified; however, iodinated contrast media are associated with risk of contrast-induced nephropathy in at-risk patients and anaphylactoid reactions.

Side Effect Profile

Serious Effects

Absolute Contraindications

["History of life-threatening anaphylactoid reaction to any iodinated contrast media","Concurrent treatment with interleukin-2 (IL-2) due to increased risk of adverse reactions","Severe hyperthyroidism (thyrotoxicosis)"]

Clinical Precautions

Precautions

["Contrast-induced acute kidney injury (CI-AKI), especially in patients with pre-existing renal impairment or diabetes mellitus","Anaphylactoid reactions, including severe hypotension and bronchospasm","Thyrotoxicosis in patients with untreated hyperthyroidism","Extravasation risk leading to local tissue injury"]

Clinical Tips & Counseling

Drug interactions

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ISOPAQUE 440

Clinical safety rating: caution

Comprehensive clinical and safety monograph for ISOPAQUE 440 (ISOPAQUE 440).

How it works

Iodinated radiocontrast agent that attenuates X-rays by increasing the iodine content in tissues, providing enhanced visualization of vasculature and organs during imaging procedures.

What the body does with it

Metabolism	Not metabolized; excreted unchanged via glomerular filtration with minimal tubular reabsorption.
Excretion	Primarily renal excretion via glomerular filtration. Approximately 95% of the administered dose is excreted unchanged in the urine within 24 hours. Less than 5% is eliminated via biliary/fecal routes.
Half-life	Terminal elimination half-life is approximately 1.5 to 2 hours in patients with normal renal function. May be prolonged in renal impairment, correlating with creatinine clearance; dose adjustment not typically required for diagnostic procedures.
Protein binding	Low protein binding: approximately 5% bound to plasma proteins, mainly albumin.
Volume of Distribution	Volume of distribution is approximately 0.2–0.3 L/kg, consistent with distribution primarily in extracellular fluid. Indicates minimal tissue penetration, remaining largely intravascular/extracellular.
Bioavailability	Not applicable for oral administration; administered intravenously or intra-arterially. Bioavailability is 100% via intravascular routes.
Onset of Action	Intravenous administration: immediate (within seconds) for contrast enhancement during imaging. Intra-arterial: immediate as bolus reaches target vessels. No oral administration; strictly parenteral.
Duration of Action	Duration of contrast enhancement is approximately 5–10 minutes for dynamic studies (CT, angiography), with rapid redistribution and elimination. Functional imaging window may extend up to 30 minutes but diminishes quickly.

Classification & Brands

Dosing & administration

Dosage form	INJECTABLE
Renal impairment	eGFR <30 mL/min/1.73m²: avoid use; eGFR 30-45: use lowest necessary dose, ensure adequate hydration, and consider stopping metformin 48h before; no specific dose reduction formula.
Liver impairment	No dose adjustment recommended for hepatic impairment; caution in severe disease due to potential coagulation abnormalities.
Pediatric use	Weight-based: 1.0-2.0 mL/kg (0.44-0.88 g iodine/kg) for CT; maximum single dose not to exceed 4.0 mL/kg (1.76 g iodine/kg); adjust for body size and imaging indication.
Geriatric use	No specific dose adjustment; consider age-related renal function decline; use lowest effective dose, ensure adequate hydration, and monitor renal function before and after administration.

Use during pregnancy

1st trimester	Consult provider
2nd trimester	Consult provider
3rd trimester	Consult provider

Clinical note

Comprehensive clinical and safety monograph for ISOPAQUE 440 (ISOPAQUE 440).

Breastfeeding	Minimal excretion into breast milk. M/P ratio not established for metrizoate. Iodinated contrast agents are considered compatible with breastfeeding; however, a 12-24 hour interruption of breastfeeding may be considered to minimize infant exposure to free iodide.
Teratogenic Risk	Isopaque 440 (metrizoate) is an ionic iodinated contrast agent. Fetal risks: First trimester - theoretical risk of fetal thyroid dysfunction from iodine exposure; however, limited human data show no consistent teratogenicity. Second and third trimesters - potential for neonatal hypothyroidism if used near term due to fetal thyroid uptake of free iodide. The drug crosses the placenta.

Warnings & precautions

■ FDA Black Box Warning

None identified; however, iodinated contrast media are associated with risk of contrast-induced nephropathy in at-risk patients and anaphylactoid reactions.