Risk factors for potential drug-drug interactions in patients with chronic obstructive pulmonary disease

Potential drug-drug interactions (pDDIs) are especially frequent in patients with chronic obstructive pulmonary disease (COPD) who, if hospitalized, experience, on average 6.5 pDDIs on admission, and 7.2 on discharge. The aim of our study was to identify and analyze risk and/or protective factors for occurrence of pDDIs in hospitalized patients with COPD. Main outcome was occurrence of pDDIs in COPD patients ascertained by Medscape, Epocrates, and Micromedex interaction checkers. The most serious pDDIs (contraindicated/serious/major/use alternative) were found in 16 (22%), 8 (11%), and 35 (49%) patients, according to the Medscape, Epocrates, and Micromedex, respectively. The COPD patients who were prescribed more drugs (especially antiarrhythmic and anticoagulants), by several independent prescribers, and having more comorbidities, were more prone to experience a pDDI; the only protective factor against pDDIs was age of the patients. In conclusion, COPD patients with the abovementioned risk factors should have their therapy more intensely monitored for pDDIs.