B. Zahner et al., Once-daily versus twice-daily vigabatrin: Is there a difference? The results of a double-blind pilot study, EPILEPSIA, 40(3), 1999, pp. 311-315
Purpose: Vigabatrin (VGB) has been approved in Europe and is prescribed for
either once or twice-daily administration. This choice has been based on t
he pharmacodynamic activity of VGB. The purpose of this study was to compar
e the efficacy and tolerability of these two different medication regimens.
Methods: The study design was a double-blind randomized two-period cross-ov
er study in adults who had responded to add-on VGB for previously uncontrol
led seizures. Each study period consisted of three months. Patients were ma
intained on the same daily dose of VGB to which they had demonstrated a cli
nical response. In addition to the primary efficacy criteria of seizure fre
quency on the two treatment regimens, this study included blinded ratings o
f overall efficacy and "well being" by both physician and patient. The prim
ary tolerability criterion was the reported incidence of adverse events by
phase.
Results: Fifty patients were initially entered into the study, and 13 patie
nts withdrew before completion, only one reported as due to an adverse even
t. Then was no statistical difference in seizure frequency or the tolerabil
ity of the medication. Blinded physician and patient rating scales for seiz
ure control, and patient well being showed a nonstatistical trend toward on
ce-daily administration as compared with twice-daily administration.
Conclusions: This clinical study provides support for the pharmacological e
vidence that this preparation may be administered on a once or twice daily
basis, depending on the individual patient's preference, total dosage and c
o-medication.