PURPOSE: We report a series of four cases of felbamate urolithiasis.
We identified only one prior case report from 2001 of a felbamate stone.(1) Felbamate is an antiepileptic drug used to treat refractory seizures and has minor side effects when given in recommended doses.(2) We analyzed the characteristics, evaluation, management, and outcomes of this difficult group of patients.
MATERIALS AND METHODS: This was an IRB-approved retrospective chart review of all patients who presented through our institution with a diagnosis of urolithiasis, were on felbamate, and had a stone analysis consistent with a felbamate origin.
RESULTS: All the patients had refractory seizures and three of the four patients were afflicted with severe developmental delay. Presentation ranged from an incidental finding, to gross hematuria, to agitation and pain. Stones were not visible on plain x-ray with the exception of one patient who had a mixed stone composition. Decrease or cessation of the drug has not been feasible in two of the four cases and three patients have had recurrent stones. Initial stone analysis did not correctly identify the stone composition as felbamate in two cases, suggesting the possibility that the origin of these stones may not always be recognized.
CONCLUSIONS: We report on the occurrence of felbamate stones in a series of patients on high dose felbamate therapy. Accurate diagnosis is made more difficult by the clinical complexity of the patient population including severe developmental delay, the radiolucent nature of the stones, and the possibility of inaccurate analysis of the stone composition.
Written by:
Ghousheh AI, Groth TW, Fryjoff KM, Wille DF, Mandel NS, Roddy JT, Durkee CT. Are you the author?
Department of Urology at Children's Hospital of Wisconsin, Milwaukee, Wisconsin.
Reference: J Urol. 2012 Dec 20. pii: S0022-5347(12)05860-0.
doi: 10.1016/j.juro.2012.12.032
PubMed Abstract
PMID: 23262038
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