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

    Research output: Contribution to journalArticlepeer-review


    According to class M2.1 of the World Anti-Doping Agency (WADA) 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 gas chromatography−mass spectrometry (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.

    Original languageEnglish
    Pages (from-to)1755-1760
    Number of pages6
    JournalDrug Testing and Analysis
    Issue number11-12
    Publication statusPublished - 30 Oct 2019

    Bibliographical note

    This is an open access article under the terms of the Creative Commons Attribution‐NonCommercial‐NoDerivs License, which permits use and distribution in any
    medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made.
    © 2019 The Authors. Drug Testing and Analysis published by John Wiley & Sons Ltd


    • Doping
    • Disability sports
    • Intravesical instillations
    • Manipulation
    • Oxybutynin
    • oxybutynin
    • doping
    • intravesical instillations
    • manipulation
    • disability sports


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