Resumen de Phenytoin and acenocoumarol: Drug interactions with clinical impact
Carmen López Martín, D. Urdiales, Vicente Faus Felipe
Drug interactions are a significant cause of morbidity and mortality since they may result in adverse clinical events and/or decrease the therapeutic efficacy of the involved drugs. We describe the case of a patient who presented phenytoin toxicity and high INR (International Normalized Ratio) secondary to phenytoin-acenocoumarol drug interaction. The patient referred to the emergency room presenting symptoms of phenytoin toxicity, high INR 4.81 and phenytoin plasma levels were within 39.6 mcg/ml. After changing to oral valproic acid, the patient responded favourably with progressive neurological improvement and INR standardization, she was discharged four days after hospitalization. The phenytoin-acenocoumarol combined therapy is common after stroke episodes. Due to the serious impact that may be derived from its combined management we should consider using another anticonvulsant therapy alternative such as valproic acid, or perform close monitoring of INR and phenytoin levels
