Frequency and nature of drug-drug interactions in the intensive care unit.

PURPOSE: Drug-drug interactions (DDIs) may compromise patient safety. However, there are no good estimates of their frequency or understanding of their nature in the intensive care unit (ICU). The objective of this study was to determine the frequency and nature of potential DDIs (pDDIs) in the ICU when assessed in light of documented and perceived clinical relevance. METHODS: We developed a computerized algorithm to identify pDDI occurrence in ICU admissions with medication administration, on the basis of the Dutch national drug database. A panel of nine local pharmacists and intensivists completed questionnaires to classify the perceived relevance of the identified pDDI types for the ICU. A focus group discussed the conflicting classifications of relevance to reach consensus. For the pDDI types classified as relevant, we calculated their number and frequency per admission days. RESULTS: Out of 9644 admissions, 3892 had at least one pDDI. The pDDIs corresponded to 85 types, 36 of which were deemed relevant on the basis of the survey and focus group. These 36 types corresponded to 16,122 pDDIs (rate: 33.6 per 100 admission days) and 1084 unique admissions. PDDIs occurred in 11% of admissions to the general ICU, after limiting analysis to severe and relevant DDI types. The most frequently encountered drug classes were antithrombotic agents and antibacterials for systemic use. CONCLUSIONS: There are many potential DDIs with high perceived relevance in the ICU that appear to require attention and follow-up. Computerized decision support may help reduce the number of pDDIs but needs to be tailored to the environment in which it operates.

Relevance of drug-drug interaction in the ICU - perceptions of intensivists and pharmacists.

Relevancy of potential drug-drug interactions (pDDIs) is crucial in alerting system design. However, the way this relevancy is perceived is not well understood. The main objective of this study was to gauge and identify differences in perceptions of intensivists and pharmacists about pDDI relevancy in the ICU. Interactions were defined according to the national medication database using a computerized algorithm. Intensivists and pharmacists filled in a questionnaire to score their perceptions on relevancy of encountered pDDIs types. We conducted a focus group session to discuss pDDIs receiving markedly different relevancy scores. The questionnaire addressed 53 pDDI types. Pharmacists rated 29 pDDI types (54.7%) in the broad category "relevant" versus 16 (30.2%) for intensivists (p-value<0.001). The pharmacists and intensivists gave the same scores for 23 pDDI types (12 as relevant, and 11 as not relevant), and scored 30 types differently. The focus group discussion resulted in a total of 36 relevant and 17 not relevant types. Compared to the pharmacists in this panel, the intensivists were less inclined to consider a pDDI type as relevant. It is important to tailor medication databases with information about evidence and severity of pDDIs to the environment in which they are used.

On-ward participation of a hospital pharmacist in a Dutch intensive care unit reduces prescribing errors and related patient harm: an intervention study.

INTRODUCTION: Patients admitted to an intensive care unit (ICU) are at high risk for prescribing errors and related adverse drug events (ADEs). An effective intervention to decrease this risk, based on studies conducted mainly in North America, is on-ward participation of a clinical pharmacist in an ICU team. As the Dutch Healthcare System is organized differently and the on-ward role of hospital pharmacists in Dutch ICU teams is not well established, we conducted an intervention study to investigate whether participation of a hospital pharmacist can also be an effective approach in reducing prescribing errors and related patient harm (preventable ADEs) in this specific setting. METHODS: A prospective study compared a baseline period with an intervention period. During the intervention period, an ICU hospital pharmacist reviewed medication orders for patients admitted to the ICU, noted issues related to prescribing, formulated recommendations and discussed those during patient review meetings with the attending ICU physicians. Prescribing issues were scored as prescribing errors when consensus was reached between the ICU hospital pharmacist and ICU physicians. RESULTS: During the 8.5-month study period, medication orders for 1,173 patients were reviewed. The ICU hospital pharmacist made a total of 659 recommendations. During the intervention period, the rate of consensus between the ICU hospital pharmacist and ICU physicians was 74%. The incidence of prescribing errors during the intervention period was significantly lower than during the baseline period: 62.5 per 1,000 monitored patient-days versus 190.5 per 1,000 monitored patient-days, respectively (P < 0.001). Preventable ADEs (patient harm, National Coordinating Council for Medication Error Reporting and Prevention severity categories E and F) were reduced from 4.0 per 1,000 monitored patient-days during the baseline period to 1.0 per 1,000 monitored patient-days during the intervention period (P = 0.25). Per monitored patient-day, the intervention itself cost €3, but might have saved €26 to €40 by preventing ADEs. CONCLUSIONS: On-ward participation of a hospital pharmacist in a Dutch ICU was associated with significant reductions in prescribing errors and related patient harm (preventable ADEs) at acceptable costs per monitored patient-day. TRIAL REGISTRATION NUMBER: ISRCTN92487665.

Photophobia in a patient with high indinavir plasma concentrations.

An HIV-infected male patient experienced photophobia after a change in dosing regimen that resulted in substantially higher indinavir plasma levels as compared with a reference population. High indinavir levels were suspected to be the cause of photophobia in this patient.