Iohexol and metrizamide in lumbar myelography. Comparison of side effects.

In routine lumbar myelography carried out in 100 patients iohexol (n = 50) produced side effects in fewer patients (p less than 0.03), especially meningeal and cerebral (p less than 0.03), and among these a lower rate of headache (p less than 0.07), than did metrizamide. The overall frequency of afflicted patients (50% after iohexol and 72% after metrizamide) was high, mainly because of deliberate inclusion of patients with a high risk of side effects in the investigation. The side effects recorded up to six hours after the administration of the contrast medium were less frequent when using iohexol. If severe side effects are present at 24 hours or appear thereafter, as occurred in a few of the present patients after iohexol, surgical treatment or discharge of the patient is in some cases unnecessarily delayed.