Pilot study on the effects of intravesical oxybutynin hydrochloride instillations on the validity of doping control urine samples

Pilot study on the effects of intravesical oxybutynin hydrochloride instillations on the validity of doping control urine samples / Katja Walpurgis, Anja B. Scheiff, Meike Welz, Jutta Müller‐Reul, Nick Webborn, Christian Görgens, Sven Guddat, Gregor Fußhöller, Josef Dib, Mario Thevis. - (Drug Testing and Analysis (2019) 30 October 2019).
- PMID: 31670462.
- DOI: 10.1002/dta.2705


According to class M2.1 of the World Anti‐Doping Agency's (WADA's) Prohibited List, the manipulation of doping control urine samples to alter their integrity and validity is prohibited both in‐ and out‐of‐competition. However, some paraplegic athletes with an overactive bladder need to be regularly treated with anti‐cholinergic and anti‐spasmodic drugs such as oxybutynin, which are often administered intravesically to reduce the substantial side effects observed after oral application. So far, it remains unclear whether such bladder instillations have a negative impact on analytical procedures and thus represent an anti‐doping rule violation.

Within this pilot study, urine samples were collected from five paraplegic athletes before and after an intravesical oxybutynin hydrochloride instillation. The samples were routinely tested for the presence of performance‐enhancing drugs and afterwards fortified with 25 model compounds representing different classes of doping agents (anabolic agents, cannabinoids, diuretics, glucocorticoids, hormone and metabolic modulators, and stimulants) at low and medium concentrations. Additionally, the pH‐value and specific gravity were measured and the presence of oxybutynin was qualitatively determined by GC‐MS.

In initial testing procedures, all samples were tested negative. Oxybutynin was present in most of the samples but found to have no significant effect on the detectability of the 25 model compounds subsequently added to each urine specimen. Therefore, it can be concluded that intravesical instillations with oxybutynin hydrochloride do not alter the integrity and validity of doping control urine samples.


Research / Study
30 October 2019
Dib, Josef
Fußhöller, Gregor
Görgens, Christian
Guddat, Sven
Müller-Reul, Jutta
Scheiff, Anja B.
Thevis, Mario
Walpurgis, Katja
Webborn, Nick
Welz, Meike
Tampering / attempted tampering
Other organisations
Deutsche Sporthochschule Köln (DSHS) - German Sport University Cologne
European Monitoring Center for Emerging Doping Agents (EuMoCEDA)
International Paralympic Committee (IPC)
Nationale Anti Doping Agentur (NADA) - National Anti Doping Agency of Germany
University of Brighton
Doping classes
M2. Chemical And Physical Manipulation
Medical terms
Legitimate Medical Treatment
Parathlete / Parasports
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Date generated
23 October 2019
Date of last modification
15 November 2019
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