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The following message was posted to: PharmPK
I have a question about how important it is to control caffeine in BA/
BE or Food-Effect studies.
The drug does not get metabolized by CYP1A2 so metabolic interactions
can be ruled out. I understand that caffeine can affect regional
blood flow, but restricting caffeine throughout the study can also
lead to headaches for subjects that are used to drinking caffeinated
beverages on a daily basis. I would prefer to restrict it upto 4
hours after dosing but would appreciate receiving your comments.
Thanks,
Vernon
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Dear Vernon
There are many reasons behind abstaining from caffeine containing
beverages
during BE-BA studies, one of which is to avoid inteference at the
retention
time of the investigated drug if HPLC is to be used. However, if you
have a
validated method that is specific to the investigated drug in
presence of
caffiene, adminisrtation of caffine beveragres might not be a problem.
I agree with you to abstain from caffeine beverages during the first 4
hours,this interval might be elongated depending on the Tmax and
absorption
profile of the investigated drug, However, follwoing the 4 hours
periods its
preferred to collect blood or urine samples one hour before consuming
caffened beverages . Hope this helps.
Regards
Isra' Admour, M.Sc Pharm
Regualtory Affairs Director
International Pharmaceutical Research Center (IPRC)
Tel: +962-6-5627651/52/48 (ext. 225)
PO Box 963166, Amman11196, Jordan
www.iprc.com.jo
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The following message was posted to: PharmPK
Dear Vernon!
According to the European Guidance you are right, since:
"The subjects [...] should abstain from food and drinks, which
may interact with circulatory, gastrointestinal, liver or renal
function (e.g. alcoholic or xanthine-containing beverages or
certain fruit juices)."
If you are able to justify lacking interactions beforehand,
everything should be fine.
Best regards
Helmut
--
Helmut Schuetz
BEBAC
Consultancy Services for Bioequivalence and Bioavailability Studies
Neubaugasse 36/11
1070 Vienna/Austria
tel/fax +43 1 2311746
http://BEBAC.at
Bioequivalence/Bioavailability Forum at http://forum.bebac.at http://
www.goldmark.org/netrants/no-word/attach.html
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The following message was posted to: PharmPK
CYP metabolism provides a compelling reason to wash out caffeine
before - and abstain during - clinical trials. The following link
indicates that caffeine interacts with 3A4 and 1A2. If you are
studying a drug that interacts with either isoform, the protocol
should exclude caffeine.
http://www.anaesthetist.com/physiol/basics/metabol/cyp/c.htm#caffeine
Ian Davis
Director, Operations
Strategic Consulting Services
Pharsight Corp.
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