Potential drug-drug interactions in hospitalized patients with chronic heart failure and chronic obstructive pulmonary disease.
BACKGROUND
Polypharmacy is common in patients with chronic heart failure (HF) and/or chronic obstructive pulmonary disease (COPD), but little is known about the prevalence and significance of drug-drug interactions (DDIs). This study evaluates DDIs in hospitalized patients.


METHODS
We retrospectively screened medical charts over a 6-month period for diagnosis of chronic HF and/or COPD. Potential DDIs were evaluated using Lexi-Interact software.


RESULTS
Seven hundred and seventy-eight patients were included in the study (median age 75 years, 61% men). The median number of drugs on admission and discharge was 6 (interquartile range (IQR) 4-9) and 7 (IQR 5-), respectively (p = 0.10). We recorded 6.5 ±5.7 potential DDIs per patient on admission and 7.2 ±5.6 on discharge (p = 0.2). From admission to discharge, type-C and type-X potential DDIs increased (p < 0.05 for both). Type X interactions were rare (< 1%), with the combination of a β-blocker and a β2 agonist being the most common (64%). There were significantly more type-C and type-D potential DDIs in patients with chronic HF as compared to patients with COPD (p < 0.001). Patients with concomitant chronic HF and COPD had more type-C and type-X potential DDIs when compared to those with individual disease (p < 0.005). An aldosterone antagonist and ACE inhibitor/ARB were prescribed to 3% of chronic HF patients with estimated glomerular filtration rate < 30 ml/(min × 1.73 m(2)).


CONCLUSIONS
The DDIs are common in patients with chronic HF and/or COPD, but only a few appear to be of clinical significance. The increase in potential DDIs from admission to discharge may reflect better guideline implementation rather than poor clinical practice.
Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia.
Tina
T
Roblek
Hospital Pharmacy, Golnik University Clinic of Pulmonary and Allergic Diseases, Golnik, Slovenia.
Katja
K
Trobec
Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia.
Ales
A
Mrhar
Applied Cachexia Research, Department of Cardiology, Charité Medical School, Campus Virchow-Klinikum, Berlin, Germany ; Division of Cardiology, Golnik University Clinic of Pulmonary and Allergic Diseases, Golnik, Slovenia.
Mitja
M
Lainscak
chronic heart failure; chronic obstructive pulmonary disease; potential drug-drug interactions