Subtherapeutic valproic acid plasma concentrations under concomitant dipyrone therapy in an epilepsy patient—a case report
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Valproic acid (VPA) is used as a broad anticonvulsant in the treatment of general and focal epilepsy and as maintenance therapy in bipolar disorder [1, 2]. Its effects are mediated by a blockage of voltage-gated sodium channels and additional mechanisms of action, which result in an increase of brain gamma butryric acid (GABA) concentrations and a blockage of T-type calcium currents . VPA is metabolized by CYP2C9, CYP2A6, CYP2C19, and CYP2B6 [3, 4]. Due to highly variable plasma concentrations, therapeutic drug monitoring during valproate therapy is recommended with a target VPA plasma concentration (pcVPA) of 50 to 100 mg/l .
Dipyrone (DPR), also known as metamizole, is a pyrazolone derivative that is hydrolyzed to the active 4-methyl-amino-antipyrine and acts as a potent analgesic with spasmolytic properties . In some European countries, it is widely used with about 175 million defined daily doses solely prescribed in Germany in 2014, but in several countries...
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The authors declare that they have no conflict of interest.
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The informed consent of the patient was obtained.
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