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

Drug Test Anal. 2019 Nov;11(11-12):1755-1760. doi: 10.1002/dta.2705. Epub 2019 Nov 21.

Abstract

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.

Keywords: disability sports; doping; intravesical instillations; manipulation; oxybutynin.

MeSH terms

  • Administration, Intravesical
  • Doping in Sports
  • Female
  • Gas Chromatography-Mass Spectrometry / methods
  • Humans
  • Male
  • Mandelic Acids / administration & dosage
  • Mandelic Acids / urine*
  • Performance-Enhancing Substances / urine*
  • Pilot Projects
  • Substance Abuse Detection / methods*
  • Urinalysis / methods*
  • Urological Agents / administration & dosage
  • Urological Agents / urine*

Substances

  • Mandelic Acids
  • Performance-Enhancing Substances
  • Urological Agents
  • oxybutynin