Monograph: |
Iohexol
lohexol contains approximately 46.4% of I.
A white to off-white, hygroscopic, odourless powder. Very
soluble in water; freely or very soluble in methyl alcohol;
practically insoluble in ether, in chloroform, and in dichlo-
romethane. Store in airtight containers. Protect from light.
Adverse Effects and Precautions
See under the dratrizoates.
Additional neurological adverse effects may occur when nonionic iodinated contrast media such as iohexol are used for myelography. These include severe headache, backache, neck stiffness, dizziness, and leg or sciatic-type pain. Convulsions, aseptic meningitis, and mild and transitory perceptual aberrations, such as visual and speech disturbances, and confusion, may occur occasionally; rarely, more severe mental disturbances have occurred. Urinary retention has also been reported.
Effects on the nervous system. Encephalopathy which developed in a 48-year-old man with sciatica within 9 hours of iohexol administration for lumbar myelography had largely resolved 48 hours after the myelogram: complete resolution took 4 days.1 However, recovery was slow in a patient who developed paraplegia and areflexia in the legs after a similar procedure. Five months later the patient still complained of paraesthesia in her legs and could not stand without support.2
Pharmacokinetics
Following intravascular administration. 90% or more of iohexol is eliminated unchanged in the urine within 24 hours. An elimination half-life of approximately 2 hours in patients with normal renal function has been reported. Protein binding in blood is reported to be very low.
Uses and Administration
lohexol is an iodinated nonionic monomenc contrast medium that is used by injection and locally for a wide range of diagnostic procedures including myelography. angiography. urography, arthrography, and visualisation of the gastro-intestinal tract and body cavities (p. 1002). lohexol is also used to produce contrast enhancement during computed tomography, lohexol is usually available as solutions containing 30.2 to 75.5% of iohexol (equivalent to 140 to 350 mg of iodine per mL) and the dose and strength used vary according to the procedure and the route of administration.
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