Pregabalin intoxication-induced encephalopathy with triphasic waves

This report documents the case of a 79-year-old woman presenting with encephalopathy and triphasic waves (TWs) due to pregabalin (PGB) intoxication. For the two years prior to admission, she had taken PGB to treat post-herpetic neuralgia. Brain MRI revealed mild leukoaraiosis and cortical atrophy. Electroencephalography showed continuous frontal-dominant TWs. These TWs were suppressed by intravenous lorazepam, but mental function was not improved. Laboratory tests revealed prerenal azotemia, which may elevate serum PGB and cause toxic encephalopathy with TWs. After fluid therapy and discontinuation of PGB, mental status recovered completely and TWs disappeared. I conclude that PGB intoxication due to deficient renal clearance can cause a reversible encephalopathy with TWs.