Predisposition to metabolic acidosis induced by topiramate.
BACKGROUND
Metabolic acidosis induced by topiramate is a well documented but infrequent adverse event. The objective was to demonstrate the lowering of carbon dioxide serum levels, which is usually asymptomatic but may facilitate the occurrence of metabolic acidosis in patients using topiramate.


METHODS
We evaluated, prospectively, the carbon dioxide serum levels of 18 patients seen at the epilepsy clinic of our university hospital, before and 3 months after introducing topiramate.


RESULTS
Five patients were female and 13 were male, age ranging from 2 to 16 years old (mean=9. 3). Carbon dioxide mean serum levels were 25 and 21.2 mmol/L (normal = 22 to 30), before and 3 months after introducing topiramate, respectively. Dose ranged from 2.08 to 11.76 mg/kg/day (mean=6. 7mg/kg/day). Adverse events were anorexia, nausea and somnolence.


CONCLUSIONS
We conclude that the lowering of carbon dioxide serum levels induced by topiramate is mostly asymptomatic, but may facilitate the occurrence of metabolic acidosis. Since patients in use of topiramate have refractory epilepsy, they may need epilepsy surgery, and must be carefully monitored for the risk of metabolic acidosis during surgery.
Montenegro
M A
MA
Departamento de Neurologia, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, SP, Brazil.
Guerreiro
M M
MM
Scotoni
A E
AE
Guerreiro
C A
CA
D000138:Acidosis / Q000139:chemically induced*; D000293:Adolescent; D000927:Anticonvulsants / Q000009:adverse effects*; D002245:Carbon Dioxide / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D004198:Disease Susceptibility / Q000139:chemically induced; D004827:Epilepsy / Q000097:blood / Q000188:drug therapy; D005260:Female; D005632:Fructose / Q000009:adverse effects / Q000031:analogs & derivatives*; D006801:Humans; D007223:Infant; D008297:Male; D011446:Prospective Studies; D000077236:Topiramate
D000927:Anticonvulsants; D000077236:Topiramate; D002245:Carbon Dioxide; D005632:Fructose