In article <1103
[email protected]>,
"zwalanga" <
[email protected]> wrote:
> I have just had a conversation with the study author. In response to my
> query about alcohol consumption in one who cannot tolerate or take
> alcohol, he suggests grapefruit and/or grapefruit juice.
> Dr. Franco will be reading here today.
>
> Zee
...............
Something to investigate.
Grapefruit Juice and Medications: A Potential for Adverse Events
Many patients may take their medications with a glass of juice. However,
since the accidental discovery of an interaction between the calcium
channel blocker, felodipine, with grapefruit juice,1 it has now become
evident that grapefruit juice has the potential to
alter the plasma concentrations of many medications when they are taken
by mouth. In some cases, this may result in undesirable clinical effects
of medications.
Administration of grapefruit juice in humans results in a decrease in
the level of CYP3A in the intestine,2 an important site for metabolism
for many medications. This mechanism would account for the increase in
levels of medications that are metabolized by CYP3A when concomitantly
administered with grapefruit juice.
A list of medications that have been shown, in clinical studies, to have
an interaction with grapefruit juice can be found in the table below.
All of the medications, except for theophylline and itraconazole, are
known to be substrates of CYP3A. When given with grapefruit juice in
pharmacokinetic studies their availability increases. In most cases, the
clinical consequence of the pharmacokinetic interaction has not been
evaluated. However, for midazolam and triazolam, as well as for
buspirone, impairment of CNS function was observed, and for the calcium
channel blocker felodipine greater blood pressure lowering has been
observed. In contrast to the increased levels of the other medications,
the grapefruit juice interaction observed with theophylline and
itraconazole was reduced plasma concentrations. The mechanism for this
effect has not been determined.
Although the clinical consequence of the grapefruit juice interaction
with most of the listed drugs has not been evaluated, increased plasma
concentrations of many of these drugs could result in adverse outcomes.
Examples include excessive lowering of blood pressure with the calcium
channel blockers, rhabdomyolysis and the potential for renal impairment
with the HMG CoA reductase inhibitors, and adverse pulmonary effects of
amiodarone. Inconsistent use of grapefruit juice or variability in its
effect on drug metabolism could result in variable and difficult to
control plasma concentrations of other medications, where maintaining a
certain plasma concentration may be especially important, such as for
cyclosporine or for HIV protease inhibitors like saquinavir.
In light of the potential for serious adverse outcomes, patients taking
medications with a potential for interaction with grapefruit juice
should be advised to avoid drinking grapefruit juice. Possible
interactions with whole grapefruit have not been evaluated but it would
be assumed to have similar effects.
Drug Class (Therapeutic Uses)
Medication
Brand Names
Antidepressant (depression)
Sertraline
Zoloft
Antihypertensive (high blood pressure)
Felodipine
Plendil
Nisoldipine
Sular
Pranidipine
Not available in the United States
Antilipemic (lowers cholesterol)
Atorvastatin
Lipitor
Lovastatin
Mevacor
Simvastatin
Zocor
Antimalarial (malaria infection)
Artemether
Paluther
Antiretroviral (HIV infection)
Saquinavir
Fortovase, Invirase
Anxiolytic (anxiety); Sedative (sleep)
Diazepam
Valium
Midazolam
Versed
Triazolam
Halcion
Buspirone
BuSpar
Bronchodilator (asthma, bronchospam)
Theophylline
Theo-Dur, Slo-bid, others
GI stimulant (stimulates GI motility)
Cisapride
Propulsid
Estrogen (birth control, hormone replacement therapy)
Ethinyl estradiol
Ortho-Novum, Loestrin, femhrt, others
Immune suppressant (prevents organ rejection)
Cyclosporine
Neoral, Sandimmune, SangCya
Antifungal (fungal infection)
Itraconazole
Sporanox
Antiarryhthmic (heart rhythm)
Amiodarone
Cordarone, Pacerone
Note: Medication names are hyperlinked to references in PubMed
1. Bailey DG, Spence JD, Munoz C, Arnold JMO.
Interaction of citrus juices with felodipine and nifedipine. Lancet
1991; 337:268-9.
2. Lown KS, Bailey DG, Fontana RJ, et al.
Grapefruit juice increases felodipine oral availability in humans by
decreasing intestinal CYP3A protein expression.
Return to Drug Interaction Advisory Index
The University of Arizona Center for Education and Research on
Therapeutics
Arizona Health Sciences Center
Tucson, Arizona 85724-5018
Funded in part by Agency for Healthcare Research and Quality grant 1 U18
HS10385-01
Disclaimer and Waiver
The information presented is intended solely for the purpose of
providing general information about health related matters. It is not
intended for any other purpose, including, but not limited to, medical
or pharmaceutical advice and/or treatment, nor is it intended to
substitute for the users' relationships with their own health
care/pharmaceutical providers. To that extent, by continued use of this
program, the user affirms the understanding of the purpose and releases
the University of Arizona, State of Arizona and Arizona Board of Regents
from any claims arising out of his/her use of the website.
--
Zone 5 S Jersey USA Shade
Serious Vision Problems like Starghart¹s ?
-->
http://www.ocutech.com/
