Survey of therapeutic drug monitoring practices in pediatric health care programs across Canada

Abstract

Background: Therapeutic drug monitoring (TDM) is helpful in situations where a drug has a narrow therapeutic index, a drug dosage does not reliably predict serum concentration, or a serum drug concentration has surrogate value (i.e., is reflective of clinical outcomes). TDM is especially important for the pediatric population, where wide variability in pharmacokinetics and differences in body composition and drug disposition exist. Unfortunately, very little is known about pediatric TDM patterns and the factors that affect the ordering of serum drug measurements. Objectives: To describe TDM practice for pediatric patients in Canada, to report on the drugs that are monitored and how they are monitored, and to discern factors that influence pediatric TDM patterns. Methods: An electronic survey was developed with online survey software and was disseminated to 42 pediatric health care centres in Canada over the period January to March 2016. Results: Of the 42 sites invited to participate in the survey, 20 (48%) responded. All sites reported performing TDM for pediatric patients, and the median number of drugs monitored was 18.5 (range 9–28) per site. The sites differed in terms of TDM practice (e.g., indications for TDM, types of serum drug measurements). Pharmacogenetic testing currently does not play a major role in TDM. Reported barriers to TDM practice include perceived lack of clinical value for certain drugs, limited access to analytical testing, and delayed return of test results. Conclusions: TDM practice is widespread in Canada. To better utilize TDM for clinical practice, future efforts can be aimed toward increasing awareness of the clinical value of TDM and improving the timeliness of access to TDM results.