Valproic acid-induced encephalopathy in very long course treated patients

Abstract

Primary objective: In patients receiving valproate (VPA) treatment, valproate induced-encephalopathy (VIE) is among the most serious adverse side-effects and hyperammonaemia is a frequent and well-recognized event. This report evaluates adult patients receiving VPA for several years.Research design: This study was conducted in adult patients receiving VPA for several years. Many studies have evaluated blood ammonia levels and VPA-related encephalopathy in patients whose treatment was initiated for a few months. Most studies were conducted in children.Methods and procedures: This study looked at retrospectively occurrences of VIE in 63 patients who were receiving VPA for a minimum duration of at least 2 years. At the beginning of the study basal ammonaemia was measured for all patients.Main outcomes and results: This study reports a rather frequent onset of VIE. Long duration of VPA treatment was not correlated with encephalopathy onset. In seven cases temporary administration of lactulose alone was effective and VPA was continued.Conclusions: This study confirms that, under VPA treatment, hyperammonaemia is a current event; 25.4% patients presented isolated elevated ammonaemia when receiving VPA for very long durations. VPA therapy should be monitored closely and clinicians must be warned of VPA encephalopathy signs.