iodixanol

Iodixanol is a nonionic iodinated contrast agent used in radiologic imaging to enhance visualization of vascular and tissue structures. It is a dimeric compound with iso-osmolar properties to plasma (about 290 mOsm/kg). Iodixanol is marketed under the trade name Visipaque and is available in solutions containing about 270 mg of iodine per milliliter or 320 mg I/mL, suitable for intravenous, intra-arterial, or other routes depending on the procedure.

In medical use, iodixanol is employed to improve contrast in computed tomography (CT), catheter-based angiography, and urography. Its iso-osmolarity is designed to reduce nonionic osmotic shifts and may lower the risk of contrast-induced nephropathy compared with high-osmolar iodinated contrast agents, although CIN can still occur, particularly in patients with preexisting kidney impairment, dehydration, diabetes, or other risk factors.

Pharmacokinetics and mechanism: iodixanol provides radiopacity by the iodine content, increasing X-ray attenuation. It distributes mainly in the extracellular fluid and is excreted unchanged by the kidneys. In individuals with normal renal function, the plasma half-life is about 2 hours; it is prolonged in renal impairment.

Safety: iodixanol is generally well tolerated, but adverse reactions—including hypersensitivity, warmth or flushing during administration, nausea, or vomiting—can occur. Extravasation at the injection site is possible. Serious anaphylactoid reactions are rare but require prompt treatment. Use cautions in patients with iodide allergy, severe kidney disease, dehydration, or those receiving nephrotoxic drugs. In at-risk patients, metformin should be withheld for 48 hours after iodinated contrast administration.

History and regulation: iodixanol is approved for intravascular use in several countries and is marketed under the brand Visipaque.