Stupor due to possible interaction between Lorazepam and valproic acid: report of two cases.

Valproate (VPA) and lorazepam are excreted mainly by glucuronide conjugation. VPA reduces the excretion of lorazepam as a result of the administration of these two medications together. As a result of these interactions, even if rarely, serious adverse effects such as coma may develop. Herein, we present two cases of stupor which developed after the addition of lorazepam to treatment administered with VPA. The first patient was being followed for five years with a diagnosis of schizoaffective disorder. She was subjected to a treatment of VPA at 1000 mg/day and an antipsychotic drug. On the twentieth day of the treatment, Lorazepam 2.5 mg was administered as an anxiolytic. The second patient was being followed with a diagnosis of schizophrenia for nine years. A VPA treatment of 750 mg/day was initiated together with an antipsychotic treatment. On the eighth day of the treatment, Lorazepam 2.5 mg was administered. A few hours later, a stupor manifestation developed in both of the patients. Administration of the entire medication to the patients was terminated and parenteral liquid administration was initiated. The clinical profile was back to normal approximately 24-36 hours following the termination of the medication. Studies about the clinical reflections of the VPA and Lorazepam interaction are limited. However, it must be remembered that as a result of the interaction of these two medications, conditions that vary between stupor and coma may arise.