The authors investigated prospectively for a mean period of 17 months a group of 19 patients with hemifacial spasm (HF) and 8 patients with blepharospasm (BLF) treated with botulinum toxin A (BTXA) (preparation Botox) with the objective to evaluate the dynamics of the clinical action of Botox from the short-term and long-term aspect and its undesirable effects. The mean single dose of Botox in the group of patients with HF was 20.5 international units (U), in the group of patients with BLF 50.0 U. The mean interval between individual doses was 2.6 months in hemispasm and 2.4 months in blepharospasm. The onset of effect of BTXA in both diagnoses was manifested on average after 7 days, the maximal effect of therapy was between the 3 rd and 4 th week and the end of effect between the 7 th and 8 th week. During repeated administrations no significant changes in amounts or intervals between administration were made. Undesirable effects developed in approximately 15 % of the administered doses. The most frequent undesirable effect in patients with HF was paresis of the mimic muscles in the area of the commissure of the lips (10.4 %), in patients with blepharospasm ptosis of the eyelids (5.2 %). The undesirable effects were except paresis of the mimic muscles in the area of the commissure of the lips fully reversible. In both diagnoses there was no primary non-responder, in the group of patients with HF there were two secondary non-responders. The assessed results confirmed that in both i nvestigated diagnoses treatment by local application of BTXA is a safe therapeutic alternative which does not lose its effectiveness during repeated administration.

        Key words: botulinum toxin type A, blepharospasm, hemifacial spasm