After performing a search of several databases, Olubanke Dzahini, B.Pharm., M.Sc., of the Institute of Pharmaceutical Science at King’s College London and colleagues included 14 studies with a total of 206,899 patients in the meta-analysis. By compiling, comparing, and contrasting data from these studies, the researchers sought to assess the overall risk of pneumonia in patients who took first- or second-generation antipsychotics compared with those who did not take antipsychotics. They also examined the risk of pneumonia in patients who took one of six antipsychotics (clozapine, haloperidol, olanzapine, quetiapine, risperidone, and zotepine) compared with those who did not take these medications.
Compared with those who had not taken antipsychotics, those who took first-generation antipsychotics had a 69% increased risk of pneumonia, and those who took second-generation antipsychotics had a 93% increased risk. Those who had taken any of the antipsychotics included in the analysis had an 83% increased risk of pneumonia. However, the researchers found that antipsychotic use did not significantly affect the fatality rate from pneumonia compared with no antipsychotic use.
When the researchers analyzed the data on the six antipsychotics, they found that patients who took these medications had a significantly increased risk of pneumonia compared with those who did not take the medications.
Although antipsychotic use was associated with a higher risk of pneumonia, the researchers stopped short of claiming causality, citing a lack of data from randomized, controlled trials and a failure of observational studies to control for relevant confounders like tobacco use and weight. Yet they suggested ways that antipsychotics may contribute to risk.
“Antipsychotics could increase the risk of aspiration pneumonia through multiple mechanisms, including specific impairment of the protective swallowing and cough reflexes, sedation, hypersalivation, and changes in pharyngeal and laryngeal muscle tone,” the researchers wrote.
The researchers emphasized the importance of considering patients’ existing risk factors for pneumonia, including older age, chronic respiratory disease, cerebrovascular disease, dysphagia, obesity, and smoking. “Clinicians need to be vigilant for the occurrence of pneumonia in all patients who commence antipsychotics. The potential risk needs to be balanced out against the potential benefits of antipsychotic treatment in an individual,” they wrote.
For related information, see the Psychiatric News article “GI, Pulmonary Illnesses: Most Cited for Hospitalizing Clozapine Patients.”