Google Answers Logo
View Question
Q: adverse side effects of grapefruit seed extract ( Answered,   0 Comments )
Subject: adverse side effects of grapefruit seed extract
Category: Health > Conditions and Diseases
Asked by: titlebabe-ga
List Price: $2.00
Posted: 28 Feb 2003 19:57 PST
Expires: 30 Mar 2003 19:57 PST
Question ID: 169079
what are reactions or contraindications when you take grapefruit seed
extract with lexapro, bumex, topral, ambien, and xanax;
Subject: Re: adverse side effects of grapefruit seed extract
Answered By: angy-ga on 01 Mar 2003 00:43 PST
Hi, titlebabe !

As I am not a doctor, I connot give medical advice, but I can tell you
some of what's out there on the Web about the subject.

Grapefruit seed extract seems to be comparatively free of interactions
with medications but this may simply be because it has not been fully
studied as yet. A safety check with Healthwell at:

simply says: 

"At the time of writing, there were no well-known drug interactions
with grapefruit seed extract."

A site promoting the benefits of the product at:


"There are no reports of any drug interactions or contraindications of
any kind. There is a danger in drinking fresh grapefruit juice or
eating grapefruits when taking certain medications (consult a doctor).
Grapefruit seed extract contains 0.1% or less of the compounds that
increase absorption of certain medications. Consult your Physician to
be sure."

However, studies do show that grapefruit juice, and presumably other
grapefruit products, can intensify the effects of certain medications:

Headstart Vitamins comment on this at:

In the course of promoting their product (grapefruit derived pectin)
they say:

".....what type of medicine you take matters. There are only a handful
that might pose a serious problem at this time. Those include 2
cholesterol-lowering statins Mevacor and Zocor, the anti-anxiety drug
Buspar (buspirone), the allergy drug Hismanal and the heart rhythm
drug Cordarone (amiodarone.) These drugs definitely interact with
grapefruit juice and should not be combined.

Some drugs interact at a moderate level, but can be taken safely.
..... In fact, because grapefruit tends to make most drugs work more
potently, it may just be that you need a lower dosage of medication.
Moderately interacting drugs include sedatives such as Ambien and
Valium, blood pressure meds like DynaCirc, Procardia (nifedipine) and
Plendil. Also, Claritin, Viagra and Tegretol (carbamazepine.)

Sometimes grapefruit lowers absorption of certain medications. But
this is also very rare and only happens with vinblastine,
cyclosporine, Cozaar, Lanoxin (digoxin) and Allegra. "

Remember they are selling a product and a positive statement is to
their advantage.

A recently updated webpage by  D.McAuley on Global Rph , at:

is clear to read and  lists drugs which interact with grapefruit by
their pharmaceutical names rather than brand names. From your list
this includes Zolpiden (Ambien) and benzodiazaopine (Xanax).

A good article is in the Medicines Information Bulletin No.70 1998 at:

It says:

 "The clinical significance of grapefruit interactions with medicines
has only recently been recognised. The following excerpt from a review
article puts the interaction into perspective: "It is usual to
highlight interactions between drugs that increase blood levels by as
little as 30% to 50%;... ... Yet an interaction with a freely
available food product that causes increases in drug levels from 240%
to 900% has failed to arouse significant concern." [1] It is clear
that the interaction deserves consideration and that specific measures
need to be taken to avoid significant harm. "

They sensibly suggest: "If avoidance is not practical then the patient
should not take grapefruit/grapefruit juice within 10 hours before or
2 hours after the medicine. "

A review of a study can be found at Yaffe Rudden and Associates site

The article, by Lead author: William A. Kehoe, Pharm.D., MA, FCCP,
BCPS, Scientific Editor lists the various types of interaction with
various drugs and tells you what symptoms to watch out for.

To give you the  details of the brandname drugs you mention:

Ambien - is zolpiden from a new group of drugs called imidzopyridines
used for sleep disorders.
Bumex - is bymetanide, a loop diuretic used to lower blood pressure
Lexapro - is Escitalopram Oxalate, is a serotonin reuptake inhibitor,
SSRI, for major
depressive disorder. 
Toprol - is metoprolol succinate is a  beta-blocker for hypertension,
angina, and heart dosease. Xanax - is alprazolam, used for anxiety. It
is a benzodiazaopine, which should not be taken with grapefruit,
although it may be less affected than some of the others in this

Although the studies deal mainly with the effects of grapefruit juice,
or the whole fruit, the general recommendation is to avoid grapefruit
products when taking some classes of drug. In your list these would be
Ambien and Xanax. As always, if in doubt, consult your physician.

I do hope you do not suffer from a condition which involves taking all
of those medications.

Good luck.

Search strategy:

grapefruit ambien
grapefruit drug interactions
grapefruit seed extract interactions

plus a search under each drug name
There are no comments at this time.

Important Disclaimer: Answers and comments provided on Google Answers are general information, and are not intended to substitute for informed professional medical, psychiatric, psychological, tax, legal, investment, accounting, or other professional advice. Google does not endorse, and expressly disclaims liability for any product, manufacturer, distributor, service or service provider mentioned or any opinion expressed in answers or comments. Please read carefully the Google Answers Terms of Service.

If you feel that you have found inappropriate content, please let us know by emailing us at with the question ID listed above. Thank you.
Search Google Answers for
Google Answers  

Google Home - Answers FAQ - Terms of Service - Privacy Policy