Adverse side effects of metrizamide in myelography.

The adverse side effects in a series of 439 myelographies with metrizamide were analyzed. The most frequent side effect was headache, which could be differentiated as early onset headache, related to hydrodynamic modifications in the spinal fluid following lumbar puncture, and late onset headache related to a metrizamide effect. The frequency of late onset headache was at least 27%, but all together 46% of the patients had postmyelographic headache. Meningeal irritation was seen in 5%, sometimes in a severe form, mimicking a septic complication. Spinal irritation and epileptic fits were rarely seen. Striking was the occurrence of an acute psycho-organic syndrome, frequently observed after cervical myelography which was performed with a higher than usual dose of iodine. We can not confirm the general opinion that the central nervous system had a good tolerance for metrizamide.