Re: Fruit juices interact with some drugs, can reduce their efficiency

[Guest guest]

Um, is this really news? I’ve been taking Allegra

(aka fexofenadine) for years and the warning label has always said to not take

it with fruit juice due to decreased adsorption. Same goes for those

drugs that increase adsorption, that has been known for years. It makes

sense there may be more drugs that are affected by these things than is

currently known… there are all sorts of things that cause potential

interactions. Allegra also says to not take it within 2 hours of certain

antacids too, again a warning I have seen on other drugs too. It is

nice to know they are studying these things, but this article really isn’t

news assuming people read the package insert that comes with their drugs.

I for one do as I have had enough adverse reactions to what to be sure of what

I am taking and what the possible side effects are!

K.

From:

samters [mailto:samters ] On Behalf Of asfyso

Sent: Thursday, August 21, 2008 4:26 PM

samters

Subject: Fruit juices interact with some drugs, can reduce

their efficiency

New Reasons To Avoid Grapefruit And Other

Juices When Taking Certain Drugs

Drinking grapefruit juice with certain drugs could lower their effectiveness,

researchers say.

ScienceDaily (Aug. 20, 2008) — Scientists and consumers have known for

years that grapefruit juice can increase the absorption of certain drugs

— with the potential for turning normal doses into toxic overdoses. Now,

the researcher who first identified this interaction is reporting new evidence

that grapefruit and other common fruit juices, including orange and apple, can

do the opposite effect by substantially decreasing the absorption of other

drugs, potentially wiping out their beneficial effects.

The study provides a new reason to avoid drinking grapefruit juice and these

other juices when taking certain drugs, including some that are prescribed for

fighting life-threatening conditions such as heart disease, cancer,

organ-transplant rejection, and infection, the researcher says. These findings

— representing the first controlled human studies of this type of

drug-lowering interaction — were described today at the 236th National

Meeting of the American Chemical Society.

" Recently, we discovered that grapefruit and these other fruit juices

substantially decrease the oral absorption of certain drugs undergoing

intestinal uptake transport, " says study leader G. ,

Ph.D., a professor of clinical pharmacology with the University of Western

Ontario in London, Ontario. " The concern is loss of benefit of medications

essential for the treatment of serious medical conditions. "

and colleagues announced almost 20 years ago the unexpected finding that

grapefruit juice can dramatically boost the body's levels of the

high-blood-pressure drug felodipine, causing potentially dangerous effects from

excessive drug concentrations in the blood. Since then, other researchers have

identified nearly 50 medications that carry the risk of grapefruit-induced

drug-overdose interactions. As a result of the so-called " Grapefruit

Juice Effect, " some prescription drugs now carry warning labels against

taking grapefruit juice or fresh grapefruit during drug consumption.

In the most recent research, 's group had healthy volunteers take

fexofenadine, an antihistamine used to fight allergies. The volunteers consumed

the drug with either a single glass of grapefruit juice, water containing only

naringin (substance in grapefruit juice that gives the juice its bitter taste),

or water. When fexofenadine was taken with grapefruit juice, only half of the

drug was absorbed compared to taking the drug with water alone, says.

Loosing half of the amount of drugs taken into the body can be critical for the

performance certain drugs, he points out.

They also showed that the active ingredient of grapefruit juice, naringin,

appears to block a key drug uptake transporter, called OATP1A2, involved in

shuttling drugs from the small intestine to the bloodstream. Blocking this

transporter reduces drug absorption and neutralizes their potential benefits,

the researchers say. By contrast, drugs whose levels are boosted in the

presence of grapefruit juice appear to block an important drug metabolizing

enzyme, called CYP3A4, that normally breaks down drugs.

" This is just the tip of the iceberg, " says. " I'm sure

we'll find more and more drugs that are affected this way. "

To date, grapefruit, orange and apple juices have been shown to lower the

absorption of etoposide, an anticancer agent; certain beta blockers (atenolol,

celiprolol, talinolol) used to treat high blood pressure and prevent heart

attacks; cyclosporine, a drug taken to prevent rejection of transplanted

organs; and certain antibiotics (ciprofloxacin, levofloxacin, itraconazole).

But additional drugs are likely to be added to the list as physicians become

more aware of this drug-lowering interaction, says.

Orange and apple juices also appear to contain naringin-like substances that

inhibit OATP1A2, says. The chemical in oranges appears to be hesperidin,

but the chemical in apples has not yet been identified, the researchers

notes.

advises patients to consult with their doctor or pharmacist before

taking any medications with grapefruit juice or other fruits and juices. Unless

it is known to be a problem, he recommends taking most medications only with

water. This research was funded by grants from the Canadian Institutes of

Health Research and the United States Public Health Service.

[Guest guest]

This information is news to me. Thank you. I appreciate all of the

good information you bring to this group.

>

> New Reasons To Avoid Grapefruit And Other Juices When Taking Certain

> Drugs

> Drinking grapefruit juice with certain drugs could lower their

> effectiveness, researchers say.

>

> ScienceDaily (Aug. 20, 2008) — Scientists and consumers have known

> for years that grapefruit juice can increase the absorption of certain

> drugs — with the potential for turning normal doses into toxic

> overdoses. Now, the researcher who first identified this interaction is

> reporting new evidence that grapefruit and other common fruit juices,

> including orange and apple, can do the opposite effect by substantially

> decreasing the absorption of other drugs, potentially wiping out their

> beneficial effects.

>

> The study provides a new reason to avoid drinking grapefruit juice and

> these other juices when taking certain drugs, including some that are

> prescribed for fighting life-threatening conditions such as heart

> disease, cancer, organ-transplant rejection, and infection, the

> researcher says. These findings — representing the first controlled

> human studies of this type of drug-lowering interaction — were

> described today at the 236th National Meeting of the American Chemical

> Society.

>

> " Recently, we discovered that grapefruit and these other fruit juices

> substantially decrease the oral absorption of certain drugs undergoing

> intestinal uptake transport, " says study leader G. , Ph.D.,

> a professor of clinical pharmacology with the University of Western

> Ontario in London, Ontario. " The concern is loss of benefit of

> medications essential for the treatment of serious medical conditions. "

>

> and colleagues announced almost 20 years ago the unexpected

> finding that grapefruit juice can dramatically boost the body's levels

> of the high-blood-pressure drug felodipine, causing potentially

> dangerous effects from excessive drug concentrations in the blood. Since

> then, other researchers have identified nearly 50 medications that carry

> the risk of grapefruit-induced drug-overdose interactions. As a result

> of the so-called " Grapefruit Juice Effect, " some prescription drugs now

> carry warning labels against taking grapefruit juice or fresh grapefruit

> during drug consumption.

>

> In the most recent research, 's group had healthy volunteers take

> fexofenadine, an antihistamine used to fight allergies. The volunteers

> consumed the drug with either a single glass of grapefruit juice, water

> containing only naringin (substance in grapefruit juice that gives the

> juice its bitter taste), or water. When fexofenadine was taken with

> grapefruit juice, only half of the drug was absorbed compared to taking

> the drug with water alone, says. Loosing half of the amount of

> drugs taken into the body can be critical for the performance certain

> drugs, he points out.

>

> They also showed that the active ingredient of grapefruit juice,

> naringin, appears to block a key drug uptake transporter, called

> OATP1A2, involved in shuttling drugs from the small intestine to the

> bloodstream. Blocking this transporter reduces drug absorption and

> neutralizes their potential benefits, the researchers say. By contrast,

> drugs whose levels are boosted in the presence of grapefruit juice

> appear to block an important drug metabolizing enzyme, called CYP3A4,

> that normally breaks down drugs.

>

> " This is just the tip of the iceberg, " says. " I'm sure we'll find

> more and more drugs that are affected this way. "

>

> To date, grapefruit, orange and apple juices have been shown to lower

> the absorption of etoposide, an anticancer agent; certain beta blockers

> (atenolol, celiprolol, talinolol) used to treat high blood pressure and

> prevent heart attacks; cyclosporine, a drug taken to prevent rejection

> of transplanted organs; and certain antibiotics (ciprofloxacin,

> levofloxacin, itraconazole). But additional drugs are likely to be added

> to the list as physicians become more aware of this drug-lowering

> interaction, says.

>

> Orange and apple juices also appear to contain naringin-like substances

> that inhibit OATP1A2, says. The chemical in oranges appears to be

> hesperidin, but the chemical in apples has not yet been identified, the

> researchers notes.

>

> advises patients to consult with their doctor or pharmacist

> before taking any medications with grapefruit juice or other fruits and

> juices. Unless it is known to be a problem, he recommends taking most

> medications only with water. This research was funded by grants from the

> Canadian Institutes of Health Research and the United States Public

> Health Service.

>

[Guest guest]

You're right, the effect of grapefruit juice has been known for a long

time. What I think is new is that orange juice and even apple juice can

have similar effects and, more far reaching, it sounds like a lot of

flavonoids (like naringin, hesperidin) should not be taken at the same

time than medications.

>

> Um, is this really news? I've been taking Allegra (aka fexofenadine)

for

> years and the warning label has always said to not take it with fruit

juice

> due to decreased adsorption. Same goes for those drugs that increase

> adsorption, that has been known for years. It makes sense there may

be more

> drugs that are affected by these things than is currently known.

there are

> all sorts of things that cause potential interactions. Allegra also

says to

> not take it within 2 hours of certain antacids too, again a warning I

have

> seen on other drugs too. It is nice to know they are studying these

> things, but this article really isn't news assuming people read the

package

> insert that comes with their drugs. I for one do as I have had enough

> adverse reactions to what to be sure of what I am taking and what the

> possible side effects are!

>

>

>

> K.

>

>

>

> From: samters [mailto:samters ] On

Behalf Of

> asfyso

> Sent: Thursday, August 21, 2008 4:26 PM

> samters

> Subject: Fruit juices interact with some drugs, can reduce

their

> efficiency

>

>

>

> New Reasons To Avoid Grapefruit And Other Juices When Taking Certain

Drugs

> Drinking grapefruit juice with certain drugs could lower their

> effectiveness, researchers say.

>

> ScienceDaily (Aug. 20, 2008) - Scientists and consumers have known for

years

> that grapefruit juice can increase the absorption of certain drugs -

with

> the potential for turning normal doses into toxic overdoses. Now, the

> researcher who first identified this interaction is reporting new

evidence

> that grapefruit and other common fruit juices, including orange and

apple,

> can do the opposite effect by substantially decreasing the absorption

of

> other drugs, potentially wiping out their beneficial effects.

>

> The study provides a new reason to avoid drinking grapefruit juice and

these

> other juices when taking certain drugs, including some that are

prescribed

> for fighting life-threatening conditions such as heart disease,

cancer,

> organ-transplant rejection, and infection, the researcher says. These

> findings - representing the first controlled human studies of this

type of

> drug-lowering interaction - were described today at the 236th National

> Meeting of the American Chemical Society.

>

> " Recently, we discovered that grapefruit and these other fruit juices

> substantially decrease the oral absorption of certain drugs undergoing

> intestinal uptake transport, " says study leader G. ,

Ph.D., a

> professor of clinical pharmacology with the University of Western

Ontario in

> London, Ontario. " The concern is loss of benefit of medications

essential

> for the treatment of serious medical conditions. "

>

> and colleagues announced almost 20 years ago the unexpected

finding

> that grapefruit juice can dramatically boost the body's levels of the

> high-blood-pressure drug felodipine, causing potentially dangerous

effects

> from excessive drug concentrations in the blood. Since then, other

> researchers have identified nearly 50 medications that carry the risk

of

> grapefruit-induced drug-overdose interactions. As a result of the

so-called

> " Grapefruit Juice Effect, " some prescription drugs now carry warning

labels

> against taking grapefruit juice or fresh grapefruit during drug

consumption.

>

> In the most recent research, 's group had healthy volunteers

take

> fexofenadine, an antihistamine used to fight allergies. The volunteers

> consumed the drug with either a single glass of grapefruit juice,

water

> containing only naringin (substance in grapefruit juice that gives the

juice

> its bitter taste), or water. When fexofenadine was taken with

grapefruit

> juice, only half of the drug was absorbed compared to taking the drug

with

> water alone, says. Loosing half of the amount of drugs taken

into the

> body can be critical for the performance certain drugs, he points out.

>

> They also showed that the active ingredient of grapefruit juice,

naringin,

> appears to block a key drug uptake transporter, called OATP1A2,

involved in

> shuttling drugs from the small intestine to the bloodstream. Blocking

this

> transporter reduces drug absorption and neutralizes their potential

> benefits, the researchers say. By contrast, drugs whose levels are

boosted

> in the presence of grapefruit juice appear to block an important drug

> metabolizing enzyme, called CYP3A4, that normally breaks down drugs.

>

> " This is just the tip of the iceberg, " says. " I'm sure we'll

find

> more and more drugs that are affected this way. "

>

> To date, grapefruit, orange and apple juices have been shown to lower

the

> absorption of etoposide, an anticancer agent; certain beta blockers

> (atenolol, celiprolol, talinolol) used to treat high blood pressure

and

> prevent heart attacks; cyclosporine, a drug taken to prevent rejection

of

> transplanted organs; and certain antibiotics (ciprofloxacin,

levofloxacin,

> itraconazole). But additional drugs are likely to be added to the list

as

> physicians become more aware of this drug-lowering interaction,

says.

>

> Orange and apple juices also appear to contain naringin-like

substances that

> inhibit OATP1A2, says. The chemical in oranges appears to be

> hesperidin, but the chemical in apples has not yet been identified,

the

> researchers notes.

>

> advises patients to consult with their doctor or pharmacist

before

> taking any medications with grapefruit juice or other fruits and

juices.

> Unless it is known to be a problem, he recommends taking most

medications

> only with water. This research was funded by grants from the Canadian

> Institutes of Health Research and the United States Public Health

Service.

>