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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 6 of 6. This is the beginning of the thread.
Posted by Mimi on May 23, 2002, at 18:23:24
Okay, I'm done with trying to find the info by an Internet search. Can somebody tell me just what is the deal with Buspar and Grapefruit. I just found out by accident you shouldn't have one with the other. I asked my pdoc and he didn't know what I was talking about. I've read this it increases the Buspar plasma level exponentially. But just what happens to someone who mixes the two. Coincidentally, two weeks ago I had started a grapefruit a day habit. Thanks for responding.
Mimi
Posted by medlib on May 24, 2002, at 0:17:38
In reply to Buspar and Grapefruit , posted by Mimi on May 23, 2002, at 18:23:24
Hi Mimi--
Buspar is a drug which exhibits nonlinear pharmacokinetics; so, increased dosage and/or repeated doses lead to much higher serum levels than one would normally expect (i.e., twice as much Buspar leads to blood levels which are *more* than twice as high).
Buspar undergoes extensive first pass metabolism in the liver by enzymes called P450 CYP3A4. Grapefruit juice inhibits this enzyme, so metabolism of Buspar is decreased/delayed--which increases blood levels of Buspar.You and/or your pdoc might be interested in Dave Flockhart's CYP enzymes tables at
http://medicine.iupui.edu/flockhart/
Using the tables:
Under the table for Substrates (substances acted upon) check column CYP3A4.5,7. You'll find Buspar listed under Miscellaneous. Then scroll down to the next table, Inhibitors. Grapefruit juice is listed under the same CYP3A4,5,7 column.What would happen if you take Buspar and grapefruit juice together is whatever would happen if you take a substantially larger dose of Buspar--probably an increase in side effects such as gastric distress, dizziness, etc. If your Buspar dose is high to begin with, you might get a toxic buildup.
Note re Enzyme tables: Most drugs are metabolized in the liver either by CYP3A4 or by CYP2D6. If you take any 2 drugs listed as substrates under the same enzyme column, those drugs will compete for the relevant available enzymes. Metabolism of 1 or both drugs will be delayed, thus serum levels will be affected.
Note re Buspar: Taking Buspar with food will slow metabolism of this drug, also; so Buspar should be taken no less than 2 hours before or 1 hour after meals.
Hoope this helps---medlib
Posted by Mimi on May 24, 2002, at 6:21:25
In reply to Re: Buspar and Grapefruit » Mimi, posted by medlib on May 24, 2002, at 0:17:38
To medlib,
Thanks a bundle for your intelligent detailed response. It was just what I had hoped for. Mimi
Posted by Sunnely on May 24, 2002, at 19:15:22
In reply to Buspar and Grapefruit , posted by Mimi on May 23, 2002, at 18:23:24
If you dig only grapefruit juice/drug interactions, check these out:
http://www.powernetdesign.com/grapefruit
http://www.ohsu.edu/som-lipid/vol153/juice.htm
http://www.holistic-online.com/Herbal-Med/_Herbs/grapefruit-interactions-home.htm
http://healthlink.mcw.edu/article/947528512.html
http://www.globalph.com/gfruit.htm
> Okay, I'm done with trying to find the info by an Internet search. Can somebody tell me just what is the deal with Buspar and Grapefruit. I just found out by accident you shouldn't have one with the other. I asked my pdoc and he didn't know what I was talking about. I've read this it increases the Buspar plasma level exponentially. But just what happens to someone who mixes the two. Coincidentally, two weeks ago I had started a grapefruit a day habit. Thanks for responding.
> Mimi
Posted by Mimi on May 27, 2002, at 7:19:07
In reply to Re: Buspar and Grapefruit » Mimi, posted by Sunnely on May 24, 2002, at 19:15:22
Thanks a bunch, Sunnely. Mimi
Posted by beardedlady on May 27, 2002, at 8:35:53
In reply to Re: Buspar and Grapefruit, posted by Mimi on May 27, 2002, at 7:19:07
Never take any kind of meds with grapefruit juice. In fact, most folks say water is best (unless milk is indicated). That's sort of a no-brainer, eh?
beardy
This is the end of the thread.
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