Risk Factors for Arthralgias or Myalgias Associated With Quinupristin-Dalfopristin Therapy

Peggy L. Carver, Pharm.D., Emily Whang, Pharm.D., Heather L. VandenBussche, Pharm.D., Carol A. Kauffman, M.D., Preeti N. Malani, M.D.

Disclosures

Pharmacotherapy. 2003;23(2) 

In This Article

Methods

The University of Michigan Hospitals and Health Centers comprise an 850-bed tertiary care center with solid organ and bone marrow transplant services. All adult and pediatric patients who had received quinupristin-dalfopristin either through a compassionate-use protocol (February 1996-October 1999) or in the year after quinupristin-dalfopristin was added to the hospital formulary (November 1999-October 2000) were included in our study. Case patients were those who developed arthralgias or myalgias while receiving quinupristin-dalfopristin; control patients were those who received quinupristin-dalfopristin but did not develop arthralgias or myalgias. Only patients with complete medical records were assessed. Approval from the institutional review board was obtained for this retrospective chart review.

Medical records, pharmacy dispensing information, and microbiology data were reviewed. The dates, dosages, and durations of quinupristin-dalfopristin therapy were noted. Relevant clinical information, concomitant drugs, and laboratory data were recorded. Medical conditions of particular interest were chronic liver or kidney disease, hematologic malignancies, receipt of a solid organ or bone marrow transplant, dialysis, hospital stay in intensive care unit, mechanical ventilation, and recent surgery. Concurrent drugs were reviewed for potential drug interactions. Dosages of concurrent drugs metabolized by cytochrome P450 (CYP) 3A4 were recorded.

Charts were reviewed by a physician and a pharmacist, both of whom specialized in infectious diseases. Presence or absence of arthralgias or myalgias was the primary outcome assessed. Presence of pain was ascertained from progress notes of medical and nursing staff; patients had to have communicated to health care personnel that they experienced muscle or joint pain. Arthralgias or myalgias were considered associated with quinupristin-dalfopristin if they were temporally related to quinupristin-dalfopristin therapy and no other cause was identified.

Potential risk factors for arthralgias or myalgias during quinupristin-dalfopristin therapy were identified by means of univariate analysis. Either the 2 or the two-tailed Fisher's exact test was used for categorical variables. Continuous variables were compared using the Student t test or the Mann-Whitney U test. Variables that were significant in the univariate analysis were further tested by logistic regression using the forward conditional method; a p value less than 0.05 was considered statistically significant. Statistical analysis was performed using SAS 6.0 and Statview 5.0.1 (SAS Institute, Cary, NC).

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