[A pharmacoepidemiological study of potential drug interactions and their determinant factors in hospitalized...

Prescription with more than one drug increases the risk of drug-drug interaction (D-DI), therapeutic failure, high pharmacological effect, or adverse events. The objectives of this study were to estimate the frequency of potential drug-drug interactions in prescriptions for hospitalized patients, and to identify the associated factors for these prescriptions.

A secondary data analysis ofa cohort was carried out, including 284 patients at the internal medicine ward in a third level hospital in Mexico City. Age, gender, diagnosis at admission, days of hospitalization, prescription and administration of the drugs were analyzed. The potential D-DI were identified and registered according to the severity. Descriptive and crude association analyses including the outcome variable and co variables, and Poisson regression analysis for adjusting the variables were performed.

The median of age was 53+/-18 years old; 53% of the patients were women, and 34% were older than 65 years of age. Sixty-three percent of the patients received one prescription identified as potential D-DI, and 33.5% of these prescriptions were "major D-DIs". The most frequently pairs of drugs prescribed were: fluoroquinolones-hypoglycemics (20.5%), enoxaparin- nonsteroidal antiinflammatory drugs or anticoagulants (18.1%), furosemide- angiotensin converting enzyme inhibitors (ACE inhibitor) (12.2%), alopurinol-ACE inhibitor (9%), and spironolactone-ACE inhibitor (9%). Thirty-three percent of patients older than 65 years of age received a prescription including one potential D-DI. Gender and the number of drugs received were associated factors to the potential D-DI.

High percentage of prescriptions with potential D-DI makes necessary to implement educational programs or alert strategies including the identified associated factors, aimed to improve the quality of prescriptions and to reduce the risks for hospitalized patients.