Evaluation of baseline corrected QT interval and azithromycin prescriptions in an academic medical center.
BACKGROUND
Azithromycin is used in the inpatient setting for a variety of conditions. In 2013, the US Food and Drug Administration released a warning regarding risk for corrected QT (QTc) prolongation and subsequent arrhythmias. Knowledge of inpatient prescribing patterns of QTc prolonging medications with respect to patient risk factors for adverse cardiovascular events can help recognize safe use in light of these new warnings.


OBJECTIVE
To assess inpatient prescribing patterns, risk factors for QTc prolongation, and relationship between drug-drug interactions and cardiac monitoring in patients receiving azithromycin.


METHODS
Retrospective cohort study.


METHODS
One hundred inpatients ≥ 19 years of age were randomly selected from 1610 patient encounters between October 2012 and April 2013 who were administered at least 1 dose of azithromycin.


METHODS
Length of stay, reason for use, therapy duration, and concomitant medications were recorded. Telemetry charges and baseline electrocardiogram (ECG) prior to administration were assessed.


RESULTS
Seventy-nine percent of azithromycin use was empiric. Sixty-five percent of patients received a baseline ECG prior to prescribing azithromycin, of which 60% had borderline or abnormal QTc prolongation. Seventy-six percent of patients were prescribed 2 or more QTc prolonging medications, of which there were more abnormal ECGs at baseline (P = 0.03) despite having telemetry ordered less than half of the time.


CONCLUSIONS
In a cohort of hospitalized patients, azithromycin was prescribed despite risk factors for QTc prolongation and administration of interacting medications. Selection of azithromycin by providers appears to be independent from these risk factors, and education and vigilance to drug-drug interactions may be useful in limiting cardiac events with prescribing azithromycin.
Department of Medicine, Division of Infectious Diseases, University of Alabama at Birmingham, Birmingham, Alabama.
Rachael A
RA
Lee
Department of Pharmacology, University of Alabama at Birmingham, Birmingham, Alabama.
Allison
A
Guyton
Department of Pharmacology, University of Alabama at Birmingham, Birmingham, Alabama.
Danielle
D
Kunz
Department of Biostatistics, University of Alabama at Birmingham, Birmingham, Alabama.
Gary R
GR
Cutter
Department of Medicine, Division of Infectious Diseases, University of Alabama at Birmingham, Birmingham, Alabama.
Craig J
CJ
Hoesley
D000046:Academic Medical Centers; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000009:adverse effects / Q000627:therapeutic use*; D017963:Azithromycin / Q000009:adverse effects / Q000627:therapeutic use*; D053840:Brugada Syndrome; D000075224:Cardiac Conduction System Disease; D004347:Drug Interactions; D004562:Electrocardiography / Q000187:drug effects*; D005260:Female; D006801:Humans; D057970:Inappropriate Prescribing / Q000706:statistics & numerical data; D008133:Long QT Syndrome / Q000139:chemically induced*; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D012189:Retrospective Studies; D012307:Risk Factors; D013686:Telemetry / Q000295:instrumentation; D014481:United States
D000900:Anti-Bacterial Agents; D017963:Azithromycin