[Relationship between clozapine plasma levels and withdrawal symptoms]. / Relación entre los síntomas de discontinuación y los niveles plasmáticos de clozapina.

Discontinuation of clozapine and an attempt to change his medication to sertindol has led to serious psychotic and somatic symptoms in an schizophrenic patient treated with clozapine for five years, however after readministration of clozapine these symptoms rapidly disappeared. To further analyse the case we have developed an HPLC method for the measurement of plasma levels of clozapine and its main metabolite N-desmethyl clozapine in order to monitor the plasma levels of clozapine and to correlate with the clinical symptoms. The present results confirmed that after discontinuation of clozapine no measurable amount of drug or its main metabolite were present in the plasma of the patient. The correlation between the plasma levels of clozapine and the changes in the clinical state of the patient confirmed that the patient's severe psychotic and somatic symptoms were the result of discontinuation of clozapine treatment. The clozapine plasma concentration of the patient reported here was low (100 ng/ml) compared to the generally accepted plasma levels for antipsychotic action of clozapine (350 ng/ml), however the somatic and psychotic clozapine withdrawal symptoms rapidly and completely disappeared.

[Prevalence of polydipsia and water intoxication in psychiatric inpatients]. / Prevalencia de polidipsia e intoxicación por agua en pacientes psiquiátricos hospitalizados.

INTRODUCTION: The prevalence of polydipsia and water intoxication among psychiatric inpatients has been described in different countries, however few studies have been conducted in Europe. The present study was aimed at evaluating the prevalence of polydipsia and water intoxication in an European Psychiatric Hospital. METHODS: SPGU (Specific Gravity of Urine) and Normalised Diurnal Weight Gain (NDWG) were evaluated among 201 inpatients. RESULTS: Risk of polydipsia and water intoxication were found among 51% of all patients. Risk of primary polydipsia was present in 25% of patients, and primary polydipsia and risk of water intoxication among 25% of all patients. CONCLUSIONS: This is one of the unique studies of polydipsia and water intoxication in psychiatric inpatients in Europe, and the first one conducted in Spain. The development of specific preventative and clinical programmes in psychiatric patients is suggested due to the clinical relevance and high prevalence of this pathology.