Neuronal MDR-1 Gene Expression and Persistent Low Levels of Anticonvulsants in a Child with Refractory Epilepsy
| Autor: | Silvia Intruvini, Alberto Lazarowski, Mario Massaro, Angeles Schteinschnaider, Gustavo Sevlever, Adrian Rabinowicz |
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| Rok vydání: | 2004 |
| Předmět: |
Male
Phenytoin medicine.medical_specialty Gene Expression Drug resistance Gastroenterology Tuberous sclerosis Epilepsy Pharmacotherapy Internal medicine medicine Humans Pharmacology (medical) ATP Binding Cassette Transporter Subfamily B Member 1 Child P-glycoprotein Pharmacology Valproic Acid biology business.industry Brain Carbamazepine medicine.disease Drug Resistance Multiple Anesthesia biology.protein Anticonvulsants Drug Therapy Combination business medicine.drug |
| Zdroj: | Therapeutic Drug Monitoring. 26:44-46 |
| ISSN: | 0163-4356 |
| Popis: | SUMMARY: It is estimated that 20-25% of epileptic patients fail to achieve good control with antiepileptic drug (AED) treatment; thus, refractory epilepsy (RE) has been described in patients who have adequate therapeutic levels of AEDs without control of seizures. Multidrug resistance genes have been reported to be highly expressed in brain of patients with RE. Persistent low plasma levels of AEDs and high brain expression of the multidrug resistance product P-glycoprotein (P-gp) have been previously communicated in a case report of RE secondary to tuberous sclerosis. Here, the authors report a case of an 8-year-old boy diagnosed with partial RE with focal seizures who was admitted to hospital for a severe episode of subintrant crisis. The patient received polytherapy with carbamazepine (CBZ), phenytoin (PHT), and valproic acid (VA); however, habitual doses of these AEDs failed to control the patient's symptoms. AED blood levels were monitored for 25 consecutive days and showed low values in 8/25 (33%) for CBZ, 10/25 (40%) for PHT, and 25/25 (100%) for VA of samples studied. Because the patient developed focal status epilepticus, surgical treatment by callosotomy was done, resulting in a significant improvement in epileptic symptoms. The immunostaining of brain specimens showed significantly increased expression of P-gp not only in vascular endothelial cells and related astrocytes but also in neurons. Overexpression of P-gp in the brain does not explain the low blood levels of AEDs described in these cases. Different mechanisms such as drug-drug interactions and drug transporters can be involved in the results observed. The P-gp overexpression and/or its pharmacologic induction should be considered as a potential mechanism responsible for drug resistance to epilepsy treatment and highly suspected in patients with persistent subtherapeutic AEDs plasma levels. |
| Databáze: | OpenAIRE |
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