Individuals with schizophrenia who take high-dose olanzapine, quetiapine, or clozapine may face an increased risk of pneumonia, according to an analysis in JAMA Psychiatry. Broadly speaking, the findings of this population study also showed that the anticholinergic burden of an antipsychotic —not how strongly it blocks dopamine receptors—may drive pneumonia risk.
“[P]neumonia constitutes the fourth leading cause of death in [patients with] schizophrenia,” wrote Jurjen J. Luykx, M.D., Ph.D., of Amsterdam University Medical Center and colleagues. They pointed out that many schizophrenia practice guidelines provide no guidance on how to manage pneumonia or mitigate pneumonia risk. “Identification of antipsychotic drugs that are associated with pneumonia risk may better inform prevention programs [like vaccinations],” they wrote.
The researchers examined the incidence of pneumonia in 61,889 individuals aged 16 or older in Finland who received inpatient care due to schizophrenia or schizoaffective disorder between 1972 and 2014. The patients were followed for an average of 22 years, and their antipsychotic medications and doses during this time were carefully tracked.
Overall, Luykx and colleagues found a modest 15% increase in pneumonia risk among individuals taking one antipsychotic medication (monotherapy) compared with individuals taking no antipsychotics; interestingly, there was no increased pneumonia risk among individuals taking multiple antipsychotics. The pneumonia risk associated with antipsychotic monotherapy was mainly limited to individuals taking high doses of medication (at least 1.1 times the World Health Organization’s defined daily dose for a particular medication).
Specifically, high-dose quetiapine was associated with a 78% increased risk of pneumonia compared with no antipsychotic use, while high-dose olanzapine was associated with a 29% increased risk. Clozapine was associated with pneumonia risk at both high doses (44% increased risk) and standard doses (43% increased risk).
All three of these antipsychotics are anticholinergic, which means they can inhibit receptors that control involuntary functions like swallowing and saliva production (saliva has antimicrobial properties).
Luykx and colleagues said these findings highlight the value of promoting healthy eating habits in schizophrenia patients taking high-dose antipsychotics, especially older individuals. “Other prevention strategies targeting at-risk groups of patients with schizophrenia include pneumococcal pneumonia, influenza, or SARS-CoV-2 vaccination programs,” they said.
For related information, see the Psychiatric News article “Study Finds Higher-Dose Antipsychotic Polypharmacy Does Not Increase Hospitalization.”
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