Key points are not available for this paper at this time.
Long term follow up studies for one to four years have not shown any tolerance to the efficacy of the drug or any long term side effects (E H Reynolds et al, 18th epilepsy international congress, New Delhi, 1989).21-23 Vigilance for possible long term toxicity should continue because early studies of toxicity in rats and dogs showed that microvacuoles suggestive of intramyelinic oedema were reversibly formed in the white matter in a dose related manner.2425 In dogs microvacuolation was accompanied by changes in the transmission time through the central nervous system of somatosensory evoked potentials, but such changes have not been observed in patients receiving long term treatment.2627 No evidence of intramyelinic oedema has been seen in six necropsies and 23 biopsy specimens taken from patients treated with vigabatrin for a mean of 25 months (D Scholey et al, Merrell Dow files, personal communication).
C J Hawkey (Sat,) studied this question.