Iodixanol

Approved Indications:

• Diagnostic Imaging:
• Intravascular Use: For radiographic contrast enhancement in:
• Cardiovascular Imaging: Coronary angiography, left ventriculography, aortography, peripheral arteriography.
• Neuroimaging: Cerebral arteriography, carotid angiography.
• Body Imaging: Visceral angiography (hepatic, renal, mesenteric), venography.
• CT Enhancement: Contrast enhancement of computed tomography of head and body.
• Excretory Urography
• Intravenous Digital Subtraction Angiography (IV DSA)
• Myelography (intrathecal use for spinal cord and subarachnoid space imaging)
• Hysterosalpingography (for evaluation of uterine cavity and fallopian tube patency)
• Arthrography (joint imaging)

Clinically Accepted Off-Label Uses:

• Intraoperative Cholangiography during biliary surgery.
• Contrast-Enhanced Mammography in select centers.
• Endovascular Procedures such as EVAR follow-up imaging in patients with higher risk of contrast-induced nephropathy.

Route: Intravenous, intra-arterial, intrathecal, intra-cavitary — depending on the imaging procedure.

Dosage:
(Concentration expressed as mg of iodine per mL)

Intravascular:

• CT of Head and Body:
• Adults: 270–320 mg I/mL; total volume typically 50–150 mL depending on body region and diagnostic requirement.
• Angiography:
• Adults: 270–320 mg I/mL; 5–50 mL per injection site, maximum total dose generally ≤ 250 mL.
• Coronary Angiography:
• Adults: 320 mg I/mL; 5–8 mL per injection into coronary arteries.

Intrathecal (Myelography):

• Adults: 270 mg I/mL; total volume 6–15 mL depending on procedure and patient size.

Excretory Urography:

• Adults: 270–320 mg I/mL; 1 mL/kg (maximum ~100 mL).

Hysterosalpingography:

• Adults: 270 mg I/mL; 10–20 mL.

Arthrography:

• Adults: 270 mg I/mL; 5–20 mL depending on joint size.

Pediatrics:

• Dose based on weight and imaging type — generally 1–2 mL/kg (270 mg I/mL), not exceeding adult maximum dose.

Special Populations:

• Renal Impairment: Use minimum necessary dose; hydrate well before and after procedure.
• Elderly: Same dosing as adults, but extra caution for renal function.
• Hepatic Impairment: No specific adjustment, but monitor closely.

Administration Notes:

• Warm solution to body temperature before use to reduce viscosity.
• Use dedicated IV/IA access; avoid mixing with other drugs.
• Monitor patient for at least 30–60 minutes post-injection for hypersensitivity or adverse events.

Iodixanol is a nonionic, dimeric, iso-osmolar radiographic contrast agent. It contains iodine atoms bound to an organic framework. When injected into vascular or body spaces, the iodine absorbs X-rays due to its high atomic number, attenuating the beam and producing enhanced contrast between perfused structures and surrounding tissues. Iso-osmolarity reduces the risk of fluid shifts and endothelial irritation, improving tolerability compared to high-osmolar agents.

• Absorption: Administered directly into circulation or target cavity; no gastrointestinal absorption.
• Distribution: Rapid distribution into extracellular fluid space; volume of distribution ~0.26 L/kg.
• Protein Binding: Negligible (<2%).
• Metabolism: Not metabolized; excreted unchanged.
• Elimination: Primarily via kidneys through glomerular filtration.
• Half-Life: ~2 hours in healthy adults; prolonged in renal impairment.
• Onset of Imaging Effect: Immediate upon administration.
• Excretion Pathway: >95% excreted in urine within 24 hours; small amounts in feces.

• Pregnancy: No FDA category assigned; human data limited. Animal studies show no teratogenicity, but use only if clearly indicated. Avoid in first trimester unless benefits outweigh risks.
• Lactation: Minimal excretion in breast milk; absorption from infant GI tract is negligible. Breastfeeding can generally continue after administration, though some guidelines suggest discarding breast milk for 24 hours as a precaution.

• Primary Class: Nonionic, dimeric, iso-osmolar radiographic contrast medium.

• Known hypersensitivity to iodixanol or other iodinated contrast media.
• History of severe reactions to contrast agents.
• Decompensated thyrotoxicosis.
• Severe renal failure without dialysis (unless absolutely necessary and benefits outweigh risks).
• Intrathecal administration in patients with known CNS infection.

• Hypersensitivity Reactions: Ranging from mild urticaria to severe anaphylaxis; emergency equipment and trained personnel should be available.
• Contrast-Induced Nephropathy (CIN): Increased risk in elderly, dehydrated patients, diabetics, or those with pre-existing renal disease; ensure adequate hydration.
• Thyroid Dysfunction: May induce hyperthyroidism or hypothyroidism in susceptible individuals.
• Seizure Risk: Intrathecal use may provoke seizures; use anticonvulsant prophylaxis in high-risk patients.
• Cardiovascular Risks: Arrhythmias, ischemia, or hypotension in patients with severe cardiac disease.
• Extravasation: Can cause local pain, swelling, and tissue injury.

Common:

• Mild warmth or flushing
• Nausea
• Headache
• Dizziness

Less Common:

• Pruritus, rash
• Vomiting
• Injection site pain

Serious (Rare):

• Anaphylaxis
• Bronchospasm
• Hypotension or shock
• Seizures (intrathecal use)
• Acute renal failure
• Pulmonary edema

Timing: Most reactions occur within minutes to an hour after administration; delayed reactions (rash, pruritus) can occur within days.

• Nephrotoxic Drugs (e.g., aminoglycosides, NSAIDs, amphotericin B): Increased risk of nephrotoxicity.
• Metformin: Risk of lactic acidosis if renal function declines post-contrast; withhold metformin before and after procedure until renal function is confirmed.
• Beta-Blockers: May mask early signs of anaphylaxis and reduce responsiveness to epinephrine.
• Interleukin-2 Therapy: Increased risk of delayed cutaneous reactions.

No significant CYP450 metabolism interactions.

• ESUR Guidelines: Emphasize screening for renal function and thyroid disorders prior to iodinated contrast use.
• CIN Prevention: Strong recommendation for pre- and post-procedure IV hydration in at-risk patients.
• Pediatric Use: Safe when dosed by body weight; caution for thyroid suppression in neonates.
• Gadolinium Alternative: In some cases, for patients with severe iodine allergy, non-iodinated agents may be considered.

• Store at 20°C–25°C (68°F–77°F).
• Protect from light.
• Do not freeze; discard if frozen.
• Keep in original container until use.
• Warm to body temperature before administration to reduce viscosity.
• Single-use vials or bottles; discard unused portion.