Pharmacokinetics of Understudied Drugs Administered to Children per Standard of Care (PTN POPS)

Determining the appropriate dosing of several understudied drugs in children using samples collected as part of regular care.

This study will characterize the pharmacokinetics of understudied drugs that are administered to children regularly by their treating physicians. Approximately 3000 children, less than 21 years of age, are participating in the study for up to 90 days (depending on how long the drug of interest is being dosed). The Pediatric Trials Network hopes to generate data to shrink the gap between pediatric and adult dosing information available to prescribing physicians for their pediatric patients. View study data for ampicillin opportunistic/PK, doxycycline opportunistic/PK, methadone opportunistic/PK, ondansetron opportunistic/PK, or trimethoprim- sulfamethoxazole (Bactrim) opportunistic/PK on NICHD's Data and Specimen Hub (DASH).

Micky Cohen-Wolkowiez, MD, PhD, of the Duke Clinical Research Institute, discusses the PTN POPS study.


Many drugs prescribed in Asia, Europe and North America lack specific dosing recommendations for children. These gaps in information about pediatric drug dosing, safety, and efficacy place children at risk for adverse events and therapeutic failure.

Earlier studies relying on standard-of-care procedures have successfully characterized the pharmacokinetics (i.e., what the body does to the drug) of drugs used in children. These studies did not actually administer drugs to children but rather collected samples from children who were already receiving the drugs as part of standard medical care.

Similarly, in this study, understudied drugs are being administered to children by their treating physicians according to local standards of care. The only study procedure involves biological sample collection during the time of drug administration. Approximately 3000 children aged <21 years who are receiving these drugs are being enrolled and will be followed for up to 90 days.

The goal of this study is to characterize the pharmacokinetics of understudied drugs for which specific dosing recommendations and safety data are lacking. The prescribing of drugs to children will not be part of this study. By taking advantage of procedures done as part of routine medical care (for example, blood draws), this study will provide better understanding of drug exposure in children. The data collected will also provide valuable pharmacokinetic and dosing information for drugs in different pediatric age groups, as well as special pediatric populations (such as obese children).


Systemic Timolol Exposure Following Topical Application to Infantile Hemangiomas.
Drolet BA, Boakye-Agyeman F, Harper B, Holland K, Lewandowski A, Stefanko N, Melloni C, Pediatric Trials Network Steering Committee.
Journal of the American Academy of Dermatology • February 2019
Pubmed PMID: 30790601

Population Pharmacokinetics of Intramuscular and Intravenous Ketamine in Children.
Hornik CP, Gonzalez D, van den Anker J, Atz AM, Yogev R, Poindexter BB, Ng KC, Delmore P, Harper BL, Melloni C, Lewandowski A, Gelber C, Cohen-Wolkowiez M, Lee JH; Best Pharmaceuticals for Children Act – Pediatric Trials Network.
Journal of Clinical Pharmacology • April 2018
Pubmed PMID: 29677389

A Pharmacokinetic Model for Amiodarone in Infants Developed from an Opportunistic Sampling Trial and Published Literature Data.
Dallefeld SH, Atz AM, Yogev R, Sullivan JE, Al-Uzri A, Mendley SR, Laughon M, Hornik C, Melloni C, Harper B, Lewandowski A, Mitchell J, Wu H, Green TP, Cohen-Wolkowiez M.
Journal of Pharmacokinetics and Pharmacodynamics February 2018
Pubmed PMID: 29435949

Comparative Analysis of Ampicillin Plasma and Dried Blood Spot Pharmacokinetics in Neonates.
Le J, Poindexter B, Sullivan JE, Laughon M, Delmore P, Blackford M, Yogev R, James LP, Melloni C, Harper B, Mitchell J, Benjamin DK Jr, Boakye-Agyeman F, Cohen-Wolkowiez M
Therapeutic Drug Monitoring • February 2018
PMCID: PMC5764797

Population Pharmacokinetics of Trimethoprim-Sulfamethoxazole in Infants and Children.
Autmizguine J, Melloni C, Hornik CP, Dallefeld S, Harper B, Yogev R, Sullivan JE, Atz AM, Al-Uzri A, Mendley S, Poindexter B, Mitchell J, Lewandowski A, Delmore P, Cohen-Wolkowiez M, Gonzalez D; the Pediatric Trials Network Steering Committee.
Antimicrobial Agents and Chemotherapy • December 2017, volume 62, issue 1.
PMCID: PMC5740321 [Free PMC article]

Clindamycin Pharmacokinetics and Safety in Preterm and Term Infants.
Gonzalez D, Delmore P, Bloom BT, Cotten CM, Poindexter BB, McGowan E, Shattuck K, Bradford KK, Smith PB, Cohen-Wolkowiez M, Morris M, Yin W, Benjamin DK, Laughon MM, on behalf of the Best Pharmaceuticals for Children Act – Pediatric Trials Network Steering Committee.
Antimicrobial Agents and Chemotherapy • April 2016, volume 60, issue 5, pages 2888-94.
PMCID: PMC4862454 [Free PMC article]

Electronic health records and pharmacokinetic modeling to assess the relationship between ampicillin exposure and seizure risk in neonates.
Hornik CP, Benjamin DK, Smith PB, Pencina MJ, Tremoulet AH, Capparelli EV, Ericson JE, Clark RH, Cohen-Wolkowiez M; Best Pharmaceuticals for Children Act – Pediatric Trials Network.
The Journal of Pediatrics November 2016, volume 178, pages 125-129.
PMCID: PMC5085855 [Free PMC article]

Simultaneous determination of trimethoprim and sulfamethoxazole in dried plasma and urine spots.
Gonzalez D, Melloni C, Poindexter BB, Yogev R, Atz AM, Sullivan JE, Mendley SR, Delmore P, Delinsky A, Zimmerman K, Lewandowski A, Harper B, Lewis KC, Benjamin DK Jr, Cohen-Wolkowiez M; Best Pharmaceuticals for Children Act – Pediatric Trials Network Administrative Core Committee.
Bioanalysis • May 2015, volume 7, issue 9, pages 1137-149.
PMCID: PMC4455038 [Free PMC article]

Use of opportunistic clinical data and a population pharmacokinetic model to support dosing of clindamycin for premature infants to adolescents.
Gonzalez D, Melloni C, Yogev R, Poindexter BB, Mendley SR, Delmore P, Sullivan JE, Autmizguine J, Lewandowski A, Harper B, Watt KM, Lewis KC, Capparelli EV, Benjamin DK Jr, Cohen-Wolkowiez M.
Clinical Pharmacology and Therapeutics • October 2014, volume 96, issue 4, pages 429-437.
PMCID: PMC4169790 [Free PMC article]

Characterization of the population pharmacokinetics of ampicillin in neonates using an opportunistic study design.
Tremoulet A, Le J, Poindexter B, Sullivan JE, Laughon M, Delmore P, Salgado A, Chong SI, Melloni C, Gao J, Benjamin DK Jr, Capparelli EV, Cohen-Wolkowiez M; on behalf of the Administrative Core Committee of the Best Pharmaceuticals for Children Act — Pediatric Trials Network.
Antimicrobial Agents and Chemotherapy • June 2014, volume 58, issue 6, pages 3013-3020.
PMCID: PMC3904301 [Free PMC article]



Enrolling identifier:

NICHD Data and Specimen Hub (DASH):

Principal Investigator:
Chiara Melloni, MD, MHS
Duke Health, Durham, NC


  • PTN welcomes first sites in Australia March 27, 2018 The Pediatric Trials Network (PTN) welcomed its first two Australian sites in February. Sydney Children’s Hospitals Network and the Royal Children’s Hospital in Melbourne are now participating in PTN’s Pharmacokinetics of Understudied Drugs in Infants and Children (POPS) study. The sites are currently involved in the Paediatric Trials Network Australia (PTNA), a counterpart of PTN that ...
  • 15 IDeA sites welcomed into PTN POPS study February 6, 2018 Fifteen sites in states participating in the NIH Institutional Development Award (IDeA) program are being onboarded into the Pediatric Trials Network’s (PTN) POPS study of commonly used medications in children. The IDeA program aims to build research capacities in states that have historically received low levels of NIH funding by supporting research, faculty development, and infrastructure ...
  • PTN determines appropriate TMP/SMX dosing in infants and children November 13, 2017 The Pediatric Trials Network (PTN), with funding from the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), recently completed a multicenter study of trimethoprim/sulfamethoxazole (TMP/SMX) to determine appropriate dosing for infants and children. The results of the study were published in the journal Antimicrobial Agents and Chemotherapy on Oct. 30. TMP/SMX is ...
  • POPS Paradigm Explained August 25, 2016 PTN studies managed via the POPS paradigm seek to determine the appropriate dosing of understudied drugs in children by using samples collected as part of regular care (for example, blood draws). The data collected provides valuable pharmacokinetic and dosing information for drugs in different pediatric age groups and special pediatric populations (such as obese children). Dr. ...
  • A POPS site goes above and beyond October 14, 2014 For an example of an outstanding PTN site, look no further than Ann & Robert H. Lurie Children’s Hospital of Chicago. The top enrolling site for the POPS study, Lurie Children’s has enrolled 244 patients as of September 22. To put this number into perspective, the second highest enrolling POPS site has recruited 117 patients, ...