Renal dysfunctions/injury in adult epilepsy patients treated with carbamazepine or valproate

Objectives: Clinical and subclinical laboratory evidence of renal proximal tubular dysfunction had been reported in children with epilepsy as an adverse effect of some antiepileptic drugs (AEDs). This study aimed to determine kidney function in adult patients with monosymptomatic epilepsy of unknown etiology and treated with valproate (VPA) or carbamazepine (CBZ).

Methods: This study included 60 patients [mean age of 33.97 ± 6.70 years and treated with VPA (n = 24) or CBZ (n = 36) for mean duration of treatment of 6.03 ± 2.81years. Measurements of serum creatinine (sCr), urinary creatinine, creatinine clearance (CrCl) and serum kidney injury molecule 1 (KIM-1), markers of renal dysfunction/injury were done.

Results: Compared to controls, patients had higher sCr, KIM-1 and lower CrCl levels. Compared to patients on VPA, those on CBZ had relatively higher KIM-1 and lower CrCl levels. We reported only significant correlations between KIM-1 with sCr (r = 0.324, p = 0.001) and duration of treatment with AEDs (r = 0.301, p = 0.02).

Conclusion: Chronic VPA and CBZ therapy may be associated with subclinical renal glomerular and/or proximal tubular dysfunctions or injuries. The treating neurologist have to consider this while selection of AED on start treating patients or modifying the AED for patients at high risk of kidney injury.