Detectability of Finasteride (Propecia) in urine test
Category: Health > Medicine
Asked by: bubbahotep-ga
List Price: $20.00
17 May 2006 18:04 PDT
Expires: 16 Jun 2006 18:04 PDT
Question ID: 729897
For how long after using Finasteride (1 mg / daily), is the use of it detectable in a urine sample? I am a 30 year old male and have used Propecia (which contains Finasteride) to prevent hairloss for some years. Finasteride has been added to the list of banned substances in sports, and I need to know how long before testing should I discontinue the use of Propecia. Thanks!
Re: Detectability of Finasteride (Propecia) in urine test
Answered By: welte-ga on 17 May 2006 21:19 PDT
Hi bubbahotep-ga, and thanks for your question. The short answer to your question is about 90 hours. Here is a good poster presentation discussing the detection of finasteride in the urine and the issues that have led to it's being banned in sports (i.e., it's use as a masking agent for steroids): http://scholar.google.com/url?sa=U&q=http://www.dshs-koeln.de/biochemie/rubriken/00_home/00_fin.pdf A second paper gives a terminal half-life of 4.7-7.1 hours (see Table 2 below). The terminal half-life is the time to reduce the serum concentration by 1/2 after equilibrium is reached. Allowing about 2 hours to reach equilibrium, 88 hours would correspond to at least about 12.3 terminal half-lives or a plasma concentration of about 1/154th of the peak concentration (0.65%), so the numbers appear to be comparable to one another. Gormley GJ. Finasteride: a clinical review. Biomed Pharmacother. 1995;49(7-8):319-24. Review. Table 2: http://img152.imageshack.us/img152/7105/snapshot200605172348534nh.jpg As you can see, there is nearly a factor of 2 in the range of metabolism finasteride, so I would suggest trying a 90 hour abstinence from finasteride and asking your physician to perform a urine drug screen for you to see if it is positive, before putting yourself in the position of potentially having a positive or borderline test before a sports event. I hope this information is helpful. Please feel free to request clarification prior to rating. -welte-ga =================== Search strategy: (finasteride OR propecia) urine metabolism detection -rat -dog http://scholar.google.com/scholar?q=(finasteride+OR+propecia)+urine+metabolism+detection+-rat+-dog&hl=en&lr=&safe=off&client=firefox-a&start=20&sa=N PubMed / Ovid searches for finasteride metabolism
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