Methodologic Progress Note: Opportunistic Sampling for Pharmacology Studies in Hospitalized Children

APPLICATIONS OF OPPORTUNISTIC SAMPLING IN CLINICAL PHARMACOLOGY RESEARCH

Opportunistic sampling has been successfully used to study a variety of drugs in different pediatric populations but has been primarily used in neonates. The multicenter Pharmacokinetics of Understudied Drugs Administered to Children per Standard of Care trial has utilized this approach to evaluate the PK of over 30 drugs.⁵ Several antimicrobials have been studied through opportunistic sampling, including those frequently used in pediatric hospital medicine, such as ampicillin⁶ and clindamycin.⁷

This sampling approach may be most beneficial in studying select patients. Obese patients, who are often excluded in pediatric drug trials, have been previously included in opportunistic drug studies.⁸ The utility of opportunistic sampling to study antimicrobials, morphine and cardiac drugs has been demonstrated in neonates, both preterm and term, in whom additional blood draws can be challenging because of low total blood volume and limited vascular access.^6,7,9-12

Although the frequency of blood draws from patients admitted to pediatric hospital medicine services is generally lower than that for patients on other subspecialty services, such as critical care, we can capitalize on the high volume of patients with common diagnoses (eg, pneumonia, skin, and soft tissue infections) who are admitted to hospital medicine. Using opportunistic sampling, we can study the PK of drugs frequently used in hospital medicine, such as antibiotics, antiepileptic drugs, steroids, and pain medications. In addition, we can measure drug concentrations to study the effects of route administration, oral versus enteric tube versus intravenous, to guide not only the dosing but also the timing of transition to enteral medications. Finally, we can study drugs that are commonly used in adult and pediatric patient populations cared for by hospitalists but who are often excluded from clinical drug trials, such as patients with medical complexity, patients with medical devices (eg, nervous system shunts and tracheostomies), patients taking concomitant medications, or patients on extracorporeal devices such as dialysis, to validate drug regimens.

CONCLUSION