title: [Topiramate in monotherapy or in combination as a cause of metabolic acidosis in adults with epilepsy].
abstract: OBJECTIVE
  To determine the frequency of metabolic acidosis and its related factors in outpatients taking topiramate in monotherapy or as an adjuvant for the treatment of epilepsy.
  
  
  METHODS
  Cross-sectional analysis of arterial blood gas test of epileptic patients who received topiramate during 2010 in the Epilepsy Clinic at the National Medical Center '20 de Noviembre' in Mexico. Clinical data regarding epilepsy history and management and the common symptoms of metabolic acidosis were recorded.
  
  
  RESULTS
  We studied 32 adults with epilepsy at an outpatient epilepsy clinic who were treated with topiramate in monotherapy or in combination for at least one month. Metabolic acidosis was found in all patients (HCO3<22 Eq/L); nine were taking topiramate in monotherapy, and 23 were taking at least two antiepileptic drugs (AEDs). All of the patients were asymptomatic. We found no correlation between bicarbonate levels and the dose of the drug or the duration of treatment. The dose was significantly higher in the monotherapy group, and the bicarbonate level was lower in the patients taking more than one AEDs.
  
  
  CONCLUSIONS
  The use of concomitant AEDs increases the known effects of topiramate on serum bicarbonate levels and the presence of metabolic acidosis, and these effects appear to be independent of the number of AEDs used.
authors: Velvet J
authors: VJ
authors: Ruiz-Granados
authors: Instituto Mexicano del Seguro Social. HGZ 2 Aguascalientes, Aguascalientes, Mexico.
authors: Juan M
authors: JM
authors: Márquez-Romero
mesh_terms: D000138:Acidosis / Q000139:chemically induced*; D000328:Adult; D000927:Anticonvulsants / Q000009:adverse effects* / Q000627:therapeutic use; D003430:Cross-Sectional Studies; D004359:Drug Therapy, Combination; D004827:Epilepsy / Q000188:drug therapy*; D005260:Female; D005632:Fructose / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000627:therapeutic use; D006801:Humans; D008297:Male; D011446:Prospective Studies; D000077236:Topiramate
chemical_list: D000927:Anticonvulsants; D000077236:Topiramate; D005632:Fructose