RESUMO
After months of successful analgesic therapy with oxcarbazepine, a 52-year old woman with trigeminal neuralgia suddenly experienced episodes of heavy trigeminal attacks regularly in the evening at about the same time. Asked about changes in daily life or eating habits, she reported the ingestion of healing earth daily in the morning. After stopping the ingestion of healing earth, analgesic control of trigeminal neuralgia was restored without any changes of the initial pharmacotherapy. In daily practice, interactions which significantly influence the absorption of drugs are often overlooked. The documentation of these interactions in drug interaction databases, in the prescribing information, and in the literature is sparse though clinically relevant. Separating the ingestion of interacting substances by a time interval may not sufficiently avoid the interaction in every case. Particular caution is warranted when slow-release cation containing drugs or substances with entero-hepatic circulation are used.
Assuntos
Anticonvulsivantes/efeitos adversos , Carbamazepina/análogos & derivados , Naturologia/efeitos adversos , Neuralgia do Trigêmeo/tratamento farmacológico , Anticonvulsivantes/farmacocinética , Anticonvulsivantes/uso terapêutico , Carbamazepina/efeitos adversos , Carbamazepina/farmacocinética , Carbamazepina/uso terapêutico , Relação Dose-Resposta a Droga , Interações Medicamentosas , Feminino , Humanos , Absorção Intestinal/efeitos dos fármacos , Assistência de Longa Duração , Pessoa de Meia-Idade , Oxcarbazepina , Neuralgia do Trigêmeo/sangue , Neuralgia do Trigêmeo/etiologia , Traumatismos em Chicotada/complicaçõesRESUMO
We report a female patient who was admitted to the emergency ward with suspected cerebral ischemia and in whom transvenous clot lysis was performed. Following lysis the patient developed recurrent complex partial seizures and treatment with intravenous phenytoin was started. Initial phenytoin serum levels were within the therapeutic range. During the course of the in-hospital treatment a sudden fall of phenytoin serum levels was detected and could not be explained by pharmacokinetic changes. Only when the drug application process was further analysed the reason for the fall in serum levels became obvious. Phenytoin sodium injections had not been administered directly into the veins but had been diluted in 0.9% saline infusions. As a result phenytoin sodium injections precipitated and were retained by the particle filter, thus leading to subtherapeutic phenytoin serum levels.
