Background: No data exist regarding the value of pharmacist monitoring of drugs associated with QTc interval prolongation.
Objective: To assess the capability, clinical impact, and economic impact of pharmacists monitoring for drug-induced QTc interval prolongation in critically ill medical adult patients.
Methods: In a prospective, parallel-group study, 149 consecutive medical intensive care unit (ICU) patients prescribed a QTc interval-prolonging drug at the Los Angeles County + University of Southern California Medical Center were assigned on alternating days to an intervention group (clinical pharmacist on physician team monitored drugs using a standardized algorithm) or a standard care group (team without pharmacist using an algorithm). The monitoring algorithm used daily assessments of electrocardiograms and laboratory data to generate pharmacotherapeutic recommendations. The primary endpoint was the frequency of QTc interval prolongation (>500 msec at any time or an increase > or =60 msec over baseline). Secondary endpoints included QTc interval greater than 470 msec in women or greater than 450 msec in men, mean increase in QTc interval at 48 hours, recommendation acceptance rate, and cost of care.
Results: QTc interval prolongation occurred less frequently in the intervention group compared with the standard care group (19% vs 39%, respectively; p = 0.006). Incidence of QTc interval greater than 500 msec (13% vs 33%, respectively; p = 0.003) was also lower in the intervention group. Incidence of QTc interval increase of 60 msec or more over baseline (12% vs 21%, respectively; p = 0.12) and increase in QTc interval at 48 hours over baseline (mean +/- SD; 6.4 +/- 40.8 vs 18.2 +/- 42.3 msec, respectively; p = 0.097) were not significantly different between the groups. Algorithm-generated recommendations were accepted 70% of the time by the intervention group physician team. Total cost and cost per day were not significantly different between groups.
Conclusions: In this preliminary study, pharmacist monitoring of QTc interval-prolonging drugs using a simple algorithm was feasible and reduced the risk of QTc interval prolongation. Further studies that monitor other proarrhythmic medications are warranted.