[Pharmacoresistance to psychotropic drugs in children and adolescents: Pharmacogenetic anomalies of cytochrome P450 2D6]

OBJECTIVES

Some patients in child and adolescent psychiatry present resistance to psychotropic drugs, often resulting in polytherapy, an increased risk of adverse events, and more frequent and longer hospitalisation. Psychotropic drugs are mainly metabolised in the liver, in particular by the CYP2D6 subunit of cytochrome P450. Anomalies such as a duplication of the CYP2D6 gene related to an ultra-rapid metaboliser phenotype has been described to be linked to clinical efficacy. However, little research has been done in child and adolescent psychiatry.

METHODS

A multi-centric cross-sectional study in the southeast of France explored the relation between pharmaco-resistance to psychotropic drugs and the prevalence of duplications or polymorphisms of CYP2D6 associated with an ultra-rapid phenotype in children and adolescents with severe mental health disease.

RESULTS

Twenty-two patients have been included. The presence of an ultra-rapid phenotype concerns one patient in our study. A second patient presents a slow metaboliser phenotype.

CONCLUSIONS

This study allows a clinical characterisation of the population of pediatric drug-resistant patients whose severity and the impact of their pathology are major and require long-term care associated with repeated hospitalisations, multiple drug prescriptions and numerous side effects. However, a link between drug resistance to psychotropic drugs and CYP2D6 UFM abnormalities could not be confirmed. An additional pharmacogenetic analysis by a panel of genes applied in the metabolism, transport and action of psychotropic drugs should be considered to answer questions about the resistance and independent effects of CYP2D6.

[Predictors factors of refractory epilepsy in childhood]

The aim of this study is to identify early predictors of refractory epilepsy. From 600 epileptic children followed for at least 2 years in the department of neurology of Charles Nicolle hospital of Tunis, were identified children with refractory epilepsy. Controls were children who responded well to antiepileptic drugs and who were seizure free for at least 2years. We collected anamnestic, clinical, neuropsychological and radiological data for all children. We identified 67 children with refractory epilepsy, representing 11.6% of the initial population. At diagnosis, the average age was 9.16 years. Some factors have been identified as predictors of drug resistance epilepsy: age of onset less than one year, partial and atonic seizure, combination of several types of attacks, presence of mental retardation and pyramidal syndrome, abnormal electroencephalogram especially focal abnormalities, spike, amplitude abnormalities, interhemispheric asymmetry; and resistance to first antiepileptic drug. Symptomatic epilepsy, especially if associated with radiological lesions such as hippocampal sclerosis and structural brain malformations, was highly correlated with drug resistance. Our study suggests that the initial presentation of epilepsy could predict long-term outcome to drug resistance epilepsy if a detailed analysis of anamnestic, clinical and complementary data is established.

[Adult patients treated for focal epilepsy with antiepileptic drugs (AEDs) in combination in France: description according to the 2009 ILAE definition of AED resistance (ESPERA study)]

AIMS

To describe the adult population treated with antiepileptic drugs (AEDs) in combination for focal epilepsy according to the definition of AED resistance proposed by the International League Against Epilepsy (ILAE) in 2009 and to evaluate its implementation in current practice.

METHODS

ESPERA was a multicenter, observational, cross-sectional study with a clinical data collection covering the past 12 months conducted by neurologists. Classifications according to AED responsiveness established by investigators for each enrolled patient were revised by two experts.

RESULTS

Seventy-one neurologists enrolled 405 patients. Their mean age was 42.7 years (sex-ratioM/F 0.98). According to the investigators, 60% of epilepsies were drug-resistant, 37% drug-responsive and 3% had an undefined drug-responsiveness. After revision of experts, 71% of epilepsies were classified as drug resistant, 22% as responsive and 7% as undefined. Among the participating neurologists, 76% have made at least one error in classifying their patients according to the 2009 ILAE definition of AED resistance. Because of epilepsy, 24% of patients (age≤65) were inactive and 42% could not drive (respectively 29 and 49% of patients with AED resistant epilepsy). Half of patients had at least one other chronic condition. Number of prescribed drugs in combination and health care resource utilisation were significantly higher in patients with drug-resistant epilepsies than in patients with drug responsive epilepsies.

CONCLUSION

ESPERA study shows that the use of new definition of drug-resistance in everyday practice seems difficult without any additional training and that the social and professional disability is frequent in adults with focal epilepsies treated with polytherapy.