METHYLPREDNISOLONE INFUSION DURING ACUTE EXACERBATION OF MS - PLASMA AND CSF CONCENTRATIONS

Plasma and CSF concentrations of methylprednisolone (MP), after a high -dose intravenous administration (1,500 mg) prescribed to patients pre senting acute exacerbation of multiple sclerosis, were measured. A pla sma pharmacokinetic study with 1 CSF sample was performed in 9 patient s and 4 other patients had a single plasma sample at the time of lumba r puncture. MP plasma kinetics were similar between patients. Pharmaco kinetic parameters were very close to previous published values obtain ed in normal volunteers or patients with rheumatoid disease. Passage o f MP into the CSF was delayed since mean plasma/CSF ratio dropped dram atically from 150 at the 2nd h to 25 at the 3rd h after starting infus ion. CSF concentrations of MP were high with a mean reaching 522 mu g/ l at the 6th h. The high levels of CSF concentrations suggest that MP may have powerful pharmacological effects within the CNS. No correlati on was found between CSF concentration and the clinical response to st eroid therapy. The issues related to previous data on clinical, biolog ical and radiological effects of high-dose intravenous MP are discusse d in the light of our results.