We receive many emails enquiring about progress. As answering these takes time away from processing submissions, please email only if absolutely necessary. We are working hard to process registration and update requests as quickly as possible.

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been endorsed by the ANZCTR. Before participating in a study, talk to your health care provider and refer to this information for consumers
Trial registered on ANZCTR

Registration number
Ethics application status
Not yet submitted
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Effect of probenecid on the pharmacokinetics of cefalexin in children
Scientific title
Effect of probenecid on the pharmacokinetics of cefalexin in children
Secondary ID [1] 298387 0
Universal Trial Number (UTN)
Trial acronym
CHOC-Dip: Children on cefalexin, dose interval with probenecid
Linked study record

Health condition
Health condition(s) or problem(s) studied:
antibiotic pharmacokinetics 313073 0
Condition category
Condition code
Infection 311560 311560 0 0
Other infectious diseases

Study type
Description of intervention(s) / exposure
A single dose of probenecid 10 mg/kg (maximum of 500 mg) orally followed by cefalexin 35 mg/kg (maximum of 1g) orally administered thirty minutes later
Intervention code [1] 314630 0
Treatment: Drugs
Comparator / control treatment
no control group
Control group

Primary outcome [1] 320269 0
Total serum cefalexin and probenecid concentrations will be determined using mass spectrometry, Pharmacokinetic parameters to be assessed for each patient are area under the concentration-time curve (AUC) from 0 – 8 h (AUC0-8) and elimination half-life (t1/2)
Timepoint [1] 320269 0
tests at baseline, 30minutes, 1 hour, 90 minutes, 2 hours, 4 hours, 6 hours and 8 hours
Secondary outcome [1] 371229 0
Side effects (e.g., nausea, rash, headache), allergic reaction measured by direct questioning and direct observation by lead investigator
Timepoint [1] 371229 0
continously for eight hours

Key inclusion criteria
Male and female children aged 2-12 years
under the care of the paediatric department at Christchurch hospital
prescribed cefalexin as oral follow-on to iv treatment for osteomyelitis, septic arthritis or other serious infection
have an iv line in place (most likely a PICC line) for blood sampling
receiving no other regular medicines likely to interact with either probenecid or cefalexin
Minimum age
2 Years
Maximum age
12 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
children for whom the blood volumes required poses above-minimal risk due to concurrent medical conditions such as anaemia (physician discretion)
contraindication to probenecid eg. hypersensitivity or disorders of uric acid metabolism
contraindication to cefalexin eg. hypersensitivity
taking methotrexate (if treatment is not interrupted while the infection is being treated)
history of significant renal or hepatic disease, or current significant abnormalities in renal or liver function tests.
Children with Cystic Fibrosis

Study design
Purpose of the study
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Single group
Other design features
open-label, non-randomised, single arm pharmacokinetics study
Phase 1
Type of endpoint(s)
Statistical methods / analysis
pharmacokinetic data will be analysed using proprietary software

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment outside Australia
Country [1] 21547 0
New Zealand
State/province [1] 21547 0

Funding & Sponsors
Funding source category [1] 302928 0
Name [1] 302928 0
Cure kids
Address [1] 302928 0
c/o Ryan Chandler
PO Box 90 907
Victoria Street
West Auckland 1142
Country [1] 302928 0
New Zealand
Primary sponsor type
A/Prof Tony Walls
University of Otago
Christchurch School of Medicine
PO Box 4345
Christchurch 8140
New Zealand
Secondary sponsor category [1] 302889 0
Name [1] 302889 0
Address [1] 302889 0
Country [1] 302889 0
Other collaborator category [1] 280721 0
Name [1] 280721 0
Professor Steve Chambers, Infectious Diseases Specialist
Address [1] 280721 0
Department of Infectious Diseases
Christchurch Hospital
Private Bag 4710
Christchurch 8140
Country [1] 280721 0
New Zealand
Other collaborator category [2] 280722 0
Name [2] 280722 0
A/Prof David Reith, Paediatric pharmacologist
Address [2] 280722 0
Office of the Dean
Great King Street
Dunedin School of Medicine
University of Otago 9016
Country [2] 280722 0
New Zealand
Other collaborator category [3] 280723 0
Name [3] 280723 0
Dr Sharon Gardiner, Antimicrobial pharmacist
Address [3] 280723 0
Dept infectious diseases
Christchurch Hospital, Private Bag 4710
Christchurch 8140
Country [3] 280723 0
New Zealand

Ethics approval
Ethics application status
Not yet submitted
Ethics committee name [1] 303492 0
NZ Health and Disability Ethics Committee
Ethics committee address [1] 303492 0
Ministry of Health
PO Box 5013
Wellington 6145
Ethics committee country [1] 303492 0
New Zealand
Date submitted for ethics approval [1] 303492 0
Approval date [1] 303492 0
Ethics approval number [1] 303492 0

Brief summary
In adults, probenecid has been shown to approximately double cefalexin concentrations and half-life. To our knowledge, there are no studies investigating the effect of probenecid on the pharmacokinetics of cefalexin in children. Currently cefalexin is given in children as a three times daily dosage. Twice daily dosing would be an advantage over three times daily dosing because it avoids the requirement to consider dosing at school or day care and improves compliance. Co-administration of probenecid with cefalexin may enable this to occur.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 93846 0
A/Prof Tony Walls
Address 93846 0
University of Otago
Christchurch School of Medicine
PO Box 4345
Christchurch 8140
Country 93846 0
New Zealand
Phone 93846 0
+64 27 262 9968
Fax 93846 0
Email 93846 0
Contact person for public queries
Name 93847 0
A/Prof Tony Walls
Address 93847 0
University of Otago
Christchurch School of Medicine
PO Box 4345
Christchurch 8140
Country 93847 0
New Zealand
Phone 93847 0
+64 27 262 9968
Fax 93847 0
Email 93847 0
Contact person for scientific queries
Name 93848 0
A/Prof Tony Walls
Address 93848 0
University of Otago
Christchurch School of Medicine
PO Box 4345
Christchurch 8140
Country 93848 0
New Zealand
Phone 93848 0
+64 27 262 9968
Fax 93848 0
Email 93848 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
What data in particular will be shared?
PK data
When will data be available (start and end dates)?
Immediately following publication, no end date
Available to whom?
researchers who provide a methodologically sound proposal and on case-by-case basis at the discretion of Primary Sponsor
Available for what types of analyses?
meta-analyses and on a case by case basis
How or where can data be obtained?
access subject to approvals by Principal Investigator
What supporting documents are/will be available?
Study protocol
Ethical approval
Summary results
No Results