Patients using type 2 diabetes drugs known as thiazolidinediones, such as Actos and Avandia, in combination with the first-line treatment metformin, may be at an increased risk for developing community-acquired pneumonia, according to a new study published in the British Journal of Clinical Pharmacology. The study pitted the drug combination against sulfonylurea with metformin. Sulfonylurea drugs include the brands Diabinese, Amaryl, and Glucotrol.
For the study, researchers identified 1,803 cases of community-acquired pneumonia, or CAP, in a cohort of type 2 diabetes patients. Researchers found that patients taking thiazolidinediones with metformin were more likely to develop CAP.
There was no significant statistical difference for CAP when comparing to newer diabetes drugs known as dipeptidyl peptidase-2 (DPP-4) inhibitors in combination with metformin to sulfonylureas with metformin. Additionally, no significant statistical difference was seen in regards to CAP with any oral antidiabetic monotherapy, researchers noted.
One theory for the increased risk of pneumonia with thiazolidinediones in combination with metformin may be due to the reduced function of immune cells initiated by thiazolidinediones. The glucocorticoid-like effects in the respiratory tract may cause an increased risk of infection, researchers said.