iohexol: clinical use

Prescribing considerations

• Confirm the diagnostic indication and review previous iodinated-contrast reactions, asthma and clinically significant allergies.
• Assess renal risk, diabetes, hydration and exposure to other nephrotoxic agents before intravascular use.
• Consider thyroid disease, planned radioiodine procedures, seizure risk, cardiovascular or cerebrovascular disease, myasthenia gravis, phaeochromocytoma and sickle-cell disease.
• Ensure immediate access to resuscitation expertise and equipment.
• Use particular care in neonates, infants and young children because renal clearance and thyroid effects may be clinically important.

Contraindications and cautions

• Hypersensitivity to iohexol or an excipient
• Manifest thyrotoxicosis

Monitoring

• Assess renal function in patients at risk and ensure appropriate hydration.
• Observe after injection for immediate hypersensitivity; delayed skin reactions can occur.
• Monitor significant extravasation for tissue injury or compartment syndrome.
• Evaluate thyroid function after exposure in young children and neonates exposed during pregnancy, as specified in the product information.
• After intrathecal administration, follow neurological observation and positioning requirements.

Clinical pharmacology

Iohexol is a water-soluble, non-ionic, monomeric tri-iodinated contrast agent. Protein binding is very low; after intravenous administration it is not detectably metabolised and is eliminated mainly unchanged in urine.

Formulation and product differences

• The selected product is a solution for intravenous, intra-arterial and intrathecal administration and use in body cavities.
• Glass and polypropylene containers are described; larger polypropylene bottles require compatible auto-injector or pump systems and validated aseptic handling.
• Smaller containers are single-use and unused solution should be discarded.