[Tolerance to interferon beta-1b amongst patients with remittent recurrent multiple sclerosis after more than one year of treatment].

Introduction: Interferon beta-1b modifies the natural history of the remittent recurrent forms of multiple sclerosis. An analysis was made of its efficiency, tolerance and adverse effects on patients with over one year of treatment.

Material And Methods: 16 patients were studied (10 women, 6 men) with ages between 19 and 51 years, incapacity scale (EDSS) 2.61 +/- 1.07 and an annual rate of outbreaks before treatment of 1.65 +/- 0.25, who received 4 MUI/48 h/s.c. of interferon beta-1b x 15 days, afterwards continuing with 8 MUI/48 h/s.c. Corticoids were associated in four cases. Biochemical controls and mass neurological evaluations were carried out as well as a watch being kept for clinical and analytical secondary effects.

Results: The annual rate for outbreaks was 0.68 +/- 0.29. Amongst the most frequent adverse effects the pseudoflu syndrome was notable (87%), with an average duration of 10.46 +/- 1.4 weeks, well tolerated with paracetamol. The local reactions (87%) were light and not related to the zone of injection. The patients experienced a sensation of fatigue following the injection in 50% of the cases, although in only one case did this reach a moderate intensity. Analytical alterations were found to be 43.7%, always within the margins of grade 1 of the clinical toxicity scale. With one patient developed an acute depressive syndrome, during which treatment was interrupted, later restarted at half the maintenance dosage.

Conclusions: In our series, just as in other studies, pseudoflu syndrome and local reactions were the most frequent secondary effects. Both complications are light, of brief duration and well tolerated by the patients.