Hyperchloremic, non-anion gap, metabolic acidosis (i.e., decreased serum bicarbonate below the normal reference range in the absence of chronic respiratory alkalosis) is associated with topiramate treatment. This metabolic acidosis is caused by renal bicarbonate loss due to the inhibitory effect of topiramate on carbonic anhydrase.

In other words, topiramate (brand name: topamax), when given for longer periods, might cause metabolic acidosis and subsequently change the pH level of your urine. In addition, the level of calcium in the urine would be increased and the chances for calcium oxalate or calcium phosphate stones would be increased. To avoid it, you might want to visit a neurologist to see if topiramate might be replaced with other medication according to your neurological condition. If not, treating the metabolic acidosis by a specialist for internal diseases, preferably a nephrologist, would be recommended.