Adverse reactions in myelography.

An attempt was made to assess the usefulness of using animal models to predict the neural tolerability in man of iodinated contrast media (CM) in general, and of the new nonionic dimer iodixanol in particular. For this purpose, the results from 6 animal experiments evaluating excitative and depressive effects of subarachnoidally injected CM in nonanesthetized rabbits were compared with the results from 22 randomized double-blind clinical trials dealing with post-myelographic adverse reactions. Comparisons were made as regards the nonionic monomers metrizamide, iohexol, and iopamidol, and the dimer iotrolan. The results seem to justify the conclusion that the convulsive effects of CM can be reliably predicted from animal experiments. The animal model cannot be used to predict specific types of nonconclusive adverse reactions in man, but reflects well the differences in frequencies of minor reactions following clinical myelography with different nonionic CM. In general, the neural tolerability of iodixanol may be expected to be better than that of the nonionic monomers and approximately equal to that of iotrolan.