Topiramate renal stones

Adverse effects These are primarily related to CNS and Gl disturbances. They include impaired concentration, dizziness, ataxia, diplopia, somnolence, nervousness, and confusion, as well as nausea and weight loss. Renal stones have been reported in 1.5 percent of patients. Topiramate is teratogenic in animals, and should be avoided during pregnancy. Inducers of drug metabolism such as phenytoin and carbamazepine decrease topiramate serum concentrations by approximately 50 percent. Topiramate decreases ethinyl estradiol concentrations of oral contraceptive preparations, and individuals should supplement the amount of ethinyl estradiol. 

I Disadvantages. With rapid dosage escalation, topiramate may compromise cognitive fnnctioning, including impaired word finding and short-term memory. Therefore, low initial doses should be used, and the dose must be titrated slowly. Renal stones and weight loss also have been associated with topiramate use. The dose should be decreased in patients with renal failure. There is no parenteral formulation. 

Topiramate Blocks glutamate (AMPA) receptors T GABA effects Partial seizures Sedation, ataxia, j weight loss, j word-finding s difficulty, j renal stones i 1... 

Topiramate Sedation, mental dulling, renal stones, weight loss... 

Topiramate mean dosage 118 mg/day has been studied in 29 patients, mean age 17 years, with Tourette syndrome in a doubleblind, randomized, placebo-controUed, parallel-group study [287. Headache, diarrhea, abdominal pain, drowsiness/hjrper-somnia, cognitive slowing, and renal stones occurred with similar frequencies in the two groups. 

Urinary tract The susceptibUity factors for topiramate-induced renal stones have been studied in six subjects [321. After 5 days treatment there was a 31% reduction in mean calcium and a 40% reduction in mean citrate urinary concentrations. Dose escalation was associated with a further reduction in citrate concentration. The authors concluded that topiramate causes a profound reduction in urinary citrate concentrations, equivalent to the changes seen in distal renal tubular acidosis. 

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