Efficacy and safety of pyridoxal in West syndrome: A retrospective study

Objective: To evaluate the efficacy and safety of pyridoxal for treating West syndrome.

Methods: We retrospectively investigated pyridoxal's efficacy and safety in 117 patients with West syndrome at Saitama Children's Medical Center from July 1993 to May 2016. Pyridoxal was administered at doses of 10-50 mg/kg/day. We evaluated seizure outcomes and electroencephalographic findings at 4 weeks after pyridoxal therapy. The responders were those with complete cessation of spasms for more than 4 weeks and those with resolution of hypsarrhythmia on EEG at 1-4 weeks after pyridoxal therapy.

Results: Five of the 117 patients (4.3%) were responders. The median duration between pyridoxal therapy to spasm cessation was 6 (5-13) days. Among the responders, four had hypsarrhythmia resolution, no spasm relapse, and no other seizure types more than 2 years after pyridoxal therapy. One responder had partial seizures and spasm relapse. No serious adverse effects occurred. There were no significant differences in sex, etiologies, complication, other seizure types preceding the spasms, onset age of spasms, age of pyridoxal therapy, treatment lag, initial and maintenance doses of pyridoxal, and adverse effects between pyridoxal responders and non-responders.

Conclusions: The efficacy rate of pyridoxal monotherapy as first-line treatment for West syndrome was low. However, pyridoxal therapy showed a rapid response within 1 week and was safe. We consider pyridoxal therapy as a kind of challenge therapy during the evaluation period concerning differential diagnosis and etiologies of West syndrome and immunological risks before adrenocorticotrophic hormone therapy or vigabatrin therapy.