Urolithiasis in Patients on High Dose Felbamate

Abstract

We report 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 stone composition.

Felbamate urolithiasis

“…Felbamate was approved by the Food and Drug Administration for focal seizures and Lennox-Gastaut syndrome in 1993. Since that time, there have been few published cases detailing the development of felbamate urolithiasis, with the majority reported in paediatric patients 1 6 7. This case underscores the importance of expanding knowledge among providers regarding such conditions and medications given that the longevity for such patients continues to expand with improvements in care.…”

Drug-Induced Urolithiasis in Pediatric Patients

“…The recommended dosages are 3600 mg/day for adults and 45 mg/kg/day for children. Most of the FBMassociated side effects occur with a relatively high dose of FBM [50]. Only three reports were found in the literature about the relation between FBM and urolithiasis in the pediatric population [49][50][51].…”

“…Most of the FBMassociated side effects occur with a relatively high dose of FBM [50]. Only three reports were found in the literature about the relation between FBM and urolithiasis in the pediatric population [49][50][51]. The pathophysiology of FBMinduced urinary stones is still vague; however, high doses, concurrent lithogenic drugs, and deteriorated renal function may represent risk factors for FBM urolithiasis [49].…”

“…Analysis of FBM-induced urinary stones showed that FBM and its metabolites constitute the main component of these stones [49][50][51]. FBM stones are radiolucent unless calcium salts are integrated in their formation, and they are characterized by the presence of FBM needle-like crystals ranging from 90 to > 1300 μm in size.…”

“…FBM stones are radiolucent unless calcium salts are integrated in their formation, and they are characterized by the presence of FBM needle-like crystals ranging from 90 to > 1300 μm in size. Furthermore, they have a layered or flaky appearance and are easily fragmented with holmium laser lithotripsy [49,50]. Treatment of this type of stone…”