[When to continue or stop Clozapine therapy?]

The decision whether or not to stop clozapine therapy in schizophrenic patients depends on a lot of factors involving the benefit/risk ratio. Thus, authors successively analyse various data: the clinical status of the patient is the first one. The evaluation has to take into account short and long-term efficacies; the problem of the minimal duration of clozapine therapy required before concluding to ineffectiveness is still open: from 4 to 12 months; the question of efficacy of the drug according to the type of symptoms is also quite difficult. Efficacy on positive symptoms among schizophrenic patients seems most prominent; negative symptoms also improve but the reasons why are quite difficult to evaluate. It is sometimes difficult to indicate if the improvement in negative symptoms is independent of the improvement in positive symptoms; the patient's request and his feeling (including tolerability) are another decisional factor; because of the lack of dystonia and other extrapyramidal side effects, some patients are more compliant under clozapine therapy; the side effect (hematologic, cardiovascular, hepatic and central nervous systems) lead to discontinuation of clozapine treatment when severe. The most frequent ones are: sedation, EEG alteration, seizures, increase of liver enzymes, hypotension/collapse, hypersalivation, fever (> 38), ECG alteration, tachycardia, gastro-intestinal adverse effects, weight gain, and leucopenia. In the event of a white blood cell count (WBC) below 3,500/mm3, the patient should be evaluated immediately with respect to the WBC and the differential count (DC). Should the results confirm a WBC below 3,500/mm3 and/or reveal an absolute neutrophil granulocyte count of 2,000 to 1,500/mm3, the leucocytes and the granulocytes must be checked at least twice a week.(ABSTRACT TRUNCATED AT 250 WORDS)