Methylphenidat: Studie zu Nachweiszeiten

Detection period of urinary metaboiites of methylphenidate

20. Dezember 2006 

Schänzer, W.*, Clasing, D.**, Herpettz-Dahlmann, B.***, Guddat, S.*, Sigmund, G.*, Thevis, M.*              

* Institute of Biochemistry, German Sport University Cologne, Germany
** National Anti Doping Agency of Germany
*** Klinik für Kinder- und Jugendpsychiatrie und-psychotherapie, Uninversitätsklinikum Aachen, Germany

Methylphenidate is prohibited in sports in competition. The therapeutic use out of competition is not prohibited. In doping control the administration of methylphenidate is detected by the analysis of methylphenidate and ritalinic acid in urine. The question is, when the application of methylphenidate has to be discontinued to prevent an adverse analytical finding for the above mentioned urinary substances in doping control. To answer this question, urine specimens of 5 patients, suffering from hyperactivity Syndrome (three boys, 15, 11, 8 years
old and two girls both 10 years Old), were collected. The participants were taking
methylphenidate continuously and stopped the application after the administration of different amounts of methyphenidate (5 - 54 mg). All urine samples were collected till 68-92 hours after the last application. The samples were analysed with gas-chromatography/mass spectrometry (GC/MS) for methylphenidate and with liquid chromatography/ tandem mass spectrometry for ritalinic acid. The detailed results are presented in Table 1. Only in one volunteer methylphenidate was detected longer than 48 hours. Ritalinic acid was detected in all volunteers for more than 72 hours. After 72 hours all volunteers showed concentrations of
ritalinic acid below the minimum required Performance limit of the WADA of 300 ng/ml. Based on these results the administration of methylphenidate is recommended to be discontinued at least 4 days before competition


Tab 1: Urinary concentrations of methylphenidate and ritalinic acid after cessation of application of different amounts of methylphenidate

Patient Age/Sex Medicationand dose of Time after application Methylphenidate Ritalini acid
methylpenidate [h] [ng/ml] [ng/ml]
1 10 f Ritalin / 10 mg 19 661 28326
43 0 422
68 0 41
92 0 0
2 15 m Concerta / 54 mg 6,3 43 39791
24 19 18692
48,5 0 4634
72 0 154
3 11 m Concerta / 36 mg ca. 1 42 27021
24 19 25939
48 0 2820
72 0 223
4 8 m Medikenet / 5 mg 1 115 24761
16 15 5525
40 6 848
68 0 26
5 10 f Ritalin / 10 mg ca. 1 395 17687
24 0 9076
48 0 903
72 0 130

Weitere Informationen

Methylphenidat

 

Institut für Biochemie der DSHS Köln, letztes Update 20.12.2006