Imiro

Indications

Iohexol is an iodine-based contrast agent (dye) used to make blood vessels, organs and body spaces show up clearly on X-ray and CT scans. It is used for CT scans, angiography (imaging of blood vessels), urography (imaging of kidneys and bladder), myelography (imaging of the spinal canal), joint imaging and, taken by mouth or rectally, imaging of the gut.

How It Works

Iodine blocks X-rays. When Iohexol is in a blood vessel or body space, that area absorbs more X-rays than the surrounding tissue and appears bright on the image, so doctors can see its shape and any blockage, leak or abnormal growth. It is not broken down by the body and is passed out unchanged in the urine, mostly within 24 hours.

Dosage and Administration

Iohexol is given by a doctor, nurse or radiographer in a hospital or imaging centre, usually as an injection or infusion into a vein or artery, or into a joint or the spinal canal, or as a drink. The strength and amount depend on the type of scan, body weight, age and kidney function, and are chosen by the radiologist as prescribed. Drink plenty of fluids before and after the scan unless told otherwise.

Interactions

• Metformin: may need to be stopped around the time of the scan in people with reduced kidney function, to avoid a build-up called lactic acidosis.
• Kidney-harming medicines (such as NSAIDs and aminoglycoside antibiotics) and diuretics can increase the risk of kidney injury.
• Beta blockers can make allergic reactions harder to treat.
• Interleukin-2 increases the risk of delayed reactions.
• It can affect thyroid tests for several weeks.

Contraindications

• Previous serious reaction to Iohexol or other iodinated contrast.
• Untreated overactive thyroid (hyperthyroidism).

Side Effects

Common: a warm feeling, metallic taste, nausea, mild headache and pain at the injection site. Some people get itching or hives. After spinal use, headache, nausea and back pain are common. Delayed skin rashes can appear hours or days later.

Get urgent medical help for difficulty breathing, wheezing, swelling of the face or throat, fainting, chest pain, seizures, a widespread rash or blistering, or greatly reduced urine in the days after the scan.

Pregnancy and Lactation

Tell staff if you are or might be pregnant; contrast scans are done in pregnancy only when clearly needed, and the newborn's thyroid may be checked afterwards. Only a tiny amount passes into breast milk, and breastfeeding can usually continue normally.

Precautions and Warnings

• Tell staff about kidney disease, diabetes, previous contrast reactions, asthma, allergies, heart disease, thyroid problems, myeloma, seizures and any medicines you take.
• Kidney function may be checked before the scan.
• You will be watched for a short time after the injection for reactions.
• Not all strengths are suitable for spinal use; staff will choose the right product.

Overdose

Overdose is unlikely as it is given by trained staff. Too much can harm the kidneys, heart and lungs. Treatment is supportive with fluids, and dialysis can remove it.

Therapeutic Class

Radiographic contrast agent, non-ionic, iodinated.

Storage

Hospital product: store as directed on the pack, usually below 30°C, protected from light, out of the reach of children.