Population pharmacokinetic modeling of sustained release lithium in the serum, erythrocytes and urine of patients with bipolar disorder.

PURPOSE: Lithium (Li), the first-line treatment of bipolar disorder, was first developed as an immediate-release form with a routine therapeutic drug monitoring 12 h after the last dose. In Europe, the most commonly prescribed form is a sustained release (srLi). Yet no pharmacokinetics (PK) study has been published of srLi, administered once a day, in adults. The present study describes srLi PK in the serum and erythrocytes of bipolar patients. METHODS: To assess srLi PK, we studied prospectively 17 French bipolar patients on a median dose of 1000 mg (600-1600) for at least 2 years. Serum (S), erythrocyte (E) concentrations, and urinary (U) amount were collected over 8 h after 15 days of morning intake using monitoring electronic medical system (MEMs). Population PK parameters were estimated using the SAEM algorithm (MONOLIX 4.3.3 software). RESULTS: Using a population approach, we built a PK population model of srLi including one S compartment (VS = 23.0 L, ClS = 1.21 L h-1), one E compartment (VE = 64.7 L, ClSE = 3.63 L h-1, ClES = 9.46 L h-1), and one U compartment (F = 0.62) and estimate the ratio of concentrations to Li in E over S at 0.38 with 27% between-subject variability. CONCLUSION: This is a PK model of srLi once a day in bipolar patients using a population approach simultaneously describing Li concentrations in serum, erythrocytes, and urine which provide an estimate of the ratio of concentration in erythrocyte over serum and its between-subject variability (BSV).

Corpus callosum abnormalities in Wilson's disease.

INTRODUCTION: Wilson's disease (WD) with neurological presentation is associated with brain lesions classically localised in globus pallidus, putamen, thalamus, mesencephalon, pons and dentate nucleus. Lesions of corpus callosum (CC) have not been studied in a broad population of patients with WD. OBJECTIVE: Evaluation of the frequency of CC lesions in patients with neurological symptoms related to WD. METHOD: The authors included all patients with neurological expression of WD, followed in the French national centre for WD who had a brain MRI between March 2006 and December 2008. The localisation of brain lesions was analysed and the frequency of lesions in CC evaluated. All patients were assessed using the Unified Wilson's Disease Rating Scale. For patients with abnormalities located in CC, a clinical dysconnexion syndrome was investigated. RESULTS: Among 81 patients (45 men, mean age: 34.8 years, from 12 to 74 years) with neurological expression, 42% had white-matter lesions on fluid-attenuated inversion recovery MRI. 23.4% of patients presented CC lesions, limited to the posterior part (splenium). The severity of disability estimated by Unified Wilson's Disease Rating Scale was correlated with the presence of CC lesions on MRI. CONCLUSION: Abnormalities in CC are not unusual (23.4%). Together with lesions of basal ganglia, CC signal changes should suggest the diagnosis of WD.

[An unrecognized cause of myelopathy associated with copper deficiency: the use of denture cream]. / Une cause méconnue de myélopathie par carence en cuivre: l'utilisation de pâte adhésive dentaire.

We report two patients with myelopathy associated with copper deficiency and pancytopenia. Excessive intake of zinc can lead to a severe deficiency of copper reducing the absorption of ingested copper. The patients had in common consumption of denture adhesive paste containing zinc. In both patients, laboratory tests showed a combination of copper deficiency, hyperzincemia and increased urinary zinc level. The use of a denture cream was stopped. Copper supplementation, initially subcutaneously then oral corrected the copper deficiency and pancytopenia. Clinically, the pain faded but the gait disturbance persisted. Copper deficiency associated with the use of denture cream rich in zinc is an unrecognized cause of myelopathy associated with pancytopenia which should be diagnosed early to establish appropriate therapeutic measures to minimize neurological complications.

[Abnormal copper metabolism in adult]. / Anomalies du métabolisme du cuivre chez l'adulte.

Copper is essential for many enzymatic reactions and in neurotransmitter biosynthesis. Its deficiency or its excess has consequences on many organs, especially the liver and the brain. The biochemical tests performed in case of suspicion of copper metabolism disorder are difficult to analyse. They include the measurement of serum ceruloplasmin, serum copper and 24h urinary copper excretion. The interpretation must take into account the clinical features. We distinguish mainly: (1) copper deficiency, acquired in malabsorption or in copper diet deficiency, or related to a genetic disease (Menkes disease); (2) copper overload, acquired or from a genetic origin (Wilson disease); (3) aceruloplasminemia, reducing ferroxidase activity leading to iron overload. It is important to diagnose these diseases as some of them have an effective treatment if it is started early enough.