Vigabatrin and epilepsy: lessons learned.
OBJECTIVE
The risk factors for visual field loss attributable to vigabatrin (VAVFL) are equivocal. This multinational, prospective, observational study aimed to clarify the principal/major factors for VAVFL.


METHODS
Interim analysis of three groups with refractory partial epilepsy, stratified by age (8-12 years; >12 years) and exposure to vigabatrin (VGB). Group I comprised participants treated with VGB for >or=6 months, Group II participants previously treated with VGB for >or=6 months who had discontinued the drug for >or=6 months and Group III those never treated with VGB. Perimetry was undertaken at least every six months, for up to 36 months; results were evaluated masked to drug exposure.


RESULTS
Based upon 563 participants in the locked data set, 432 yielded one or more Conclusive visual field examinations. For Group I, the frequency of VAVFL at the last Conclusive examination was 10/32 (31.2%) for those aged 8-12 years and 52/125 (41.6%) for those aged >12 years. For Group II, the proportions were 4/39 (10.3%) and 31/129 (24.0%). No cases resembling VAVFL manifested in Group III. VAVFL was associated with duration of VGB therapy (Odds ratio [OR] 14.2; 95% CI 5.0 to 40.5); mean dose of VGB (OR 8.5; 95% CI 2.2 to 33.2); and male gender (OR 2.1; 95% CI 1.2 to 3.7). VAVFL was more common with static than kinetic perimetry (OR 2.3, 95% CI 1.3 to 4.2).


CONCLUSIONS
The therapeutic benefit of VGB is counteracted by the progressive accrual of the risk of VAVFL with continued exposure and with increase in mean dose.
Wild
John M
JM
Cardiff School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom. wildjm@cf.ac.uk
Ahn
Hyo-sook
HS
Baulac
Michel
M
Bursztyn
Joseph
J
Chiron
Catherine
C
Gandolfo
Enrico
E
Safran
Avinoam B
AB
Schiefer
Ulrich
U
Perucca
Emilio
E
D000293:Adolescent; D000367:Age Factors; D000927:Anticonvulsants / Q000009:adverse effects* / Q000627:therapeutic use; D002648:Child; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004827:Epilepsy / Q000188:drug therapy*; D005260:Female; D005500:Follow-Up Studies; D006423:Hemianopsia / Q000139:chemically induced / Q000175:diagnosis; D006801:Humans; D008297:Male; D012307:Risk Factors; D012737:Sex Factors; D020888:Vigabatrin / Q000009:adverse effects* / Q000627:therapeutic use; D014786:Vision Disorders / Q000139:chemically induced* / Q000175:diagnosis; D058609:Visual Field Tests / Q000706:statistics & numerical data; D014794:Visual Fields / Q000187:drug effects
D000927:Anticonvulsants; D020888:Vigabatrin