202 - Summary

Summary

Schizophrenia and related psychoses CHAPTER 1 ■ ■Assume that the use of all antipsychotics increases the risk of pneumonia, but especially clozapine and high-­dose olanzapine or quetiapine. ■ ■Concomitant benzodiazepine use should be avoided, where possible. ■ ■Monitor all patients for signs of chest infection and treat promptly. ■ ■Offer vaccination against COVID-­19, influenza and pneumococcus to all high-­risk patients. ­dopamine partial agonists) seem to have a lower risk of pneumonia than pure dopamine antagonists.9 Another study found amisulpride (a dopamine antagonist with minimal anticholinergic activity) is not linked to pneumonia.11 Mechanisms Although studies rarely distinguish between the various forms of pneumonia, cases of antipsychotic-­induced aspiration, infective (viral and bacterial) and hypersensitivity pneumonia have been documented.16 The mechanism by which antipsychotics increase the risk of such pneumonia is not known but is probably multifactorial. Proposed mechanisms are outlined in Box 1.2. An increased risk of pneumonia should probably be assumed for all patients taking any antipsychotic (but especially clozapine)21 for any period. All patients should be very carefully monitored for signs of chest infection and effective treatment started promptly. Consideration should be given to using COVID-­19, influenza and pneumococcal vaccines, although there is no direct evidence to support benefit for pneumonia prevention in this specific group of patients. Those patients prescribed clozapine should be proactively monitored and treated for hypersalivation. Pneumonia is likely to increase clozapine levels (see section on clozapine: common adverse effects in this chapter) so close monitoring is required. Slower-­than-­usual clozapine titration may prevent cases of hypersensitivity pneumonia.14 Extra vigilance is required when re-­exposing to patients with history of clozapine-­induced pneumonia who are taking clozapine. With all cases, early referral to general medical services should be considered where there is any doubt about the severity or type of chest infection. Summary Box 1.2  Proposed mechanisms for antipsychotic-­induced pneumonia ■ ■Sedation ■ ■Dystonia or dyskinesia ■ ■Dry mouth ■ ■General poor physical health ■ ■Reduced immune response* ■ ■Clozapine-specific: hypersalivation, constipation * Clozapine is associated with antibody deficiency and greater use of antibiotics. This increased risk of infection is not related to neutrophil counts.20