Atypical antipsychotic drugs and diabetes

Abstract

Atypical antipsychotic drugsSchizophrenia is a syndrome characterised by a broad range of cognitive, emotional and behavioural problems, the prevalence of which is estimated at 0.2-1.0% in the general population. Its symptoms are classified into positive (hallucinations, delusions, formal thought disorder and bizarre behaviour) and negative (flattening of mood, emotional apathy, social withdrawal, lack of motivation and loss of pleasure). Schizophrenia has been treated largely using conventional antipsychotic drugs. However, over the last 10 years, the atypical, also known as novel or secondgeneration, antipsychotics have increasingly been used. The British National Formulary currently lists amisulpride, clozapine, olanzapine, quetiapine, risperidone, sertindole and zotepine as atypical antipsychotic drugs. From a pharmacological perspective, they are distinguished by their dual action of serotonin 2A receptor and dopamine D2 receptor antagonism as compared to the conventional antipsychotic drugs, which have an antagonistic action mainly on the D2 receptor.The atypical antipsychotics are indicated both for the treatment of schizophrenia and related disorders in which psychosis is a defining feature. However, they can also be used to quieten patients whatever the underlying psychopathology, e.g. brain damage, severe anxiety, toxic delirium or agitated depression. From a clinical perspective, atypical antipsychotic drugs have a lower incidence of extrapyramidal adverse effects than the conventional antipsychotic drugs and are more efficacious in the treatment of negative symptoms of schizophrenia. Recently, the National Institute Clinical Excellence has published guidance on the use of atypical antipsychotic drugs for the treatment of schizophrenia. 1 It is recommended that they are used as firstline treatments for individuals with newly diagnosed schizophrenia and should also be used for those patients whose management has been unsatisfactory on conventional drugs or who have experienced unacceptable adverse effects. The following two prescribing restrictions should be noted. Sertindole is available on a named patient supply only due to its cardiac adverse effects and clozapine is restricted to individuals who are intolerant or unresponsive to conventional antipsychotic drugs. The association between atypical antipsychotic drugs and diabetesIt has long been recognised that hyperglycaemia and type 2 diabetes mellitus are more common in patients with schizophrenia than in the general population. In one recent study the prevalence of diabetes in a sample population of patients with schizophrenia was 15.8% as opposed to 3.2% in the general population. 2 Type 2 diabetes is itself becoming a commoner condition in the population as a whole.Since the introduction of the atypical antipsychotic drugs it has become apparent that their use is associated with metabolic adverse effects (Table 1) diabetes. 4 In another study, patients who already had diabetes required to be switched from an oral hypoglycaemic agent to insulin o...

Diabetes, psychotic disorders and antipsychotic therapy: a consensus statement

“…Many case reports and series and a few larger studies based on administrative databases have described associations between antipsychotic treatment and the onset or exacerbation of diabetes 2 . ‐ 5 However, there are no long‐term, randomised controlled trials to guide clinical practice in this area. The existing evidence suggests that the introduction of first‐generation antipsychotic medications (FGAs, see Box 1) was associated with a two‐ to threefold increase in the prevalence of diabetes among treated patients 6 , 7 (Level III evidence [derived from pseudorandomised controlled trials, comparative studies, single‐arm studies or interrupted time series without a parallel control group 8 ]).…”