Prevalence of the Prescription of Potentially Interacting Drugs

Abstract

The use of multiple medications is becoming more common, with a correspondingly increased risk of untoward effects and drug-related morbidity and mortality. We aimed at estimating the prevalence of prescription of relevant potentially interacting drugs and at evaluating possible predictors of potentially interacting drug exposure. We retrospectively analyzed data on prescriptions dispensed from January 2004 to August 2005 to individuals of two Italian regions with a population of almost 2.1 million individuals. We identified 27 pairs of potentially interacting drugs by examining clinical relevance, documentation, and volume of use in Italy. Subjects who received at least one prescription of both drugs were selected. Co-prescribing denotes “two prescriptions in the same day”, and concomitant medication “the prescription of two drugs with overlapping coverage”. A logistic regression analysis was conducted to examine the predictors of potential Drug-Drug Interaction (pDDIs). 957,553 subjects (45.3% of study population) were exposed to at least one of the drugs/classes of the 27 pairs. Overall, pDDIs occurred 2,465,819 times. The highest rates of concomitant prescription and of co-prescription were for ACE inhibitors+NSAIDs (6,253 and 4,621/100,000 plan participants). Considering concomitance, the male/female ratio was <1 in 17/27 pairs (from 0.31 for NSAIDs-ASA+SSRI to 0.74 for omeprazole+clopidogrel). The mean age was lowest for methotrexate pairs (+omeprazole, 59.9 years; +NSAIDs-ASA, 59.1 years) and highest for digoxin+verapamil (75.4 years). In 13/27 pairs, the mean ages were ≥70 years. On average, subjects involved in pDDIs received ≥10 drugs. The odds of exposure were more frequently higher for age ≥65 years, males, and those taking a large number of drugs. A substantial number of clinically important pDDIs were observed, particularly among warfarin users. Awareness of the most prevalent pDDIs could help practitioners in preventing concomitant use, resulting in a better quality of drug prescription and potentially avoiding unwanted side effects.

Clinically important drug–drug interactions in poly‐treated elderly outpatients: a campaign to improve appropriateness in general practice

“…The prevalence rate found in our cohort falls at the low end of the range reported in previous studies in outpatients. Although a direct comparison among the different poly‐pharmacy rates is cumbersome and hard to interpret (studies may differ in terms of definition of poly‐therapy, sample age, nature of data source, units of analysis, variations in clinical practices and patients' behaviours among the different Countries), our data remarkably differ from a similar investigation performed on 2007 prescription data of the Emilia Romagna region (39%) and are more in line with most recent European and US studies, showing that 16% of the study population were exposed to drug combinations .…”

An assessment of antihypertensive drug prescription patterns and adherence to joint national committee-8 hypertension treatment guidelines among hypertensive patients attending a tertiary care teaching hospital

“…Some combinations may result in undesired pharmacodynamic or pharmacokinetic interactions, resulting in under-treatment or harmful effects. 42,43 The consequences of drug-drug interactions (DDIs) can range from no untoward effects at all, to drug-related mortality. 42,43 This study had some limitations also.…”

“…42,43 The consequences of drug-drug interactions (DDIs) can range from no untoward effects at all, to drug-related mortality. 42,43 This study had some limitations also. Data were collected from only one institution, therefore population is relatively homogenous.…”

Prevalence of Potential Drug-Drug Interactions in Hospitalized Surgical Patients

“…Moreover, DDIs are considered a risk factor for medication safety. As a result, DDIs have become a common concern and an important concept in terms of an appropriate prescription process [3]. Furthermore, the presence of DDIs in hospitalized patients is one of the major causes of adverse events [4,5].…”

“…In ambulatory patients, DDIs represent 0.1% of hospital visits and 1.1% of hospital admissions [6], resulting in increased hospital stay days, as well as higher costs D DAVID PUBLISHING associated with healthcare [7,8]. The risk factors associated with DDIs include age, the number of prescription medications, the presence of comorbidities and the number of hospital stay days [3,[9][10][11].…”