Neural tolerance of the non-ionic dimers iodixanol and iotrolan and the non-ionic monomer iopamidol during myelography in non-anaesthetised rabbits.
OBJECTIVE
The neural tolerance of the recently introduced dimer iodixanol (320 g I/l) was compared with that of the dimer iotrolan (300 g I/l) and of the monomer iopamidol (300 g I/l), both used in clinical myelography.


METHODS
Non-anaesthetised rabbits were injected into the cisterna magna with Ringer's solution (control) or contrast media (CM) at doses of 1.0 or 0.5 ml/kg b.w. The behaviour of the animals (10 in each of 7 groups) was evaluated for signs of excitation and depression during the first 3 hours after injection.


RESULTS
At the dose level of 1.0 ml/kg b.w., iodixanol produced no seizures but did cause focal twitching in 4/10 rabbits. Iopamidol produced grand mal seizures in 2/10 and hyperexcitability in 4/10 rabbits. Iotrolan produced generalised grand mal seizures in 8/10 rabbits, an incidence of excitation significantly greater than that of iodixanol (p < 0.01) and iopamidol (p < 0.05). The excitative effects of iodixanol were not significantly different from those of iopamidol and Ringer's solution. All 3 CM produced similar depressive effects on rabbit behaviour. Ringer's solution caused no depressive effects (p < 0.01). A clear dose response was produced with all 3 CM after treatment with a lower dose of 0.5 ml/kg b.w.


CONCLUSIONS
The results indicate that the neural tolerance in the rabbit of iodixanol is higher than that of iotrolan, and is at least equal to that of iopamidol.
Department of Diagnostic Radiology, Malmö University Hospital, Sweden.
P
P
Maly
P
P
Sundgren
L
L
Bååth
P
P
Walday
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D003287:Contrast Media / Q000633:toxicity*; D007479:Iopamidol / Q000633:toxicity*; D009192:Myelography; D009420:Nervous System / Q000187:drug effects*; D011817:Rabbits; D012640:Seizures / Q000175:diagnosis; D014283:Triiodobenzoic Acids / Q000633:toxicity*
D003287:Contrast Media; D014283:Triiodobenzoic Acids; C033300:iotrolan; C044834:iodixanol; D007479:Iopamidol