The Dangers of Grapefruit
and its Juice
on Certain Drugs
Certain drugs can cause serious or
occasionally life-threatening effects if consumed in combination with grapefruit
or its juice.
Background
Consuming grapefruit or its juice
(fresh or frozen) can increase, or less commonly decrease, the effects
of some drugs. There are several substances in grapefruit that interfere
with the way your body handles certain drugs.
These effects are known to be caused
by the combination of grapefruit and its juice with certain drugs and health
products used in the treatment of medical conditions, including, but not
limited to:
-
Angina
-
Anxiety
-
Cancer
-
Convulsions
-
Depression
-
Erectile dysfunction
-
Gastrointestinal reflux
-
High blood pressure
-
High lipid (cholesterol) levels
-
HIV/AIDS
-
Infections
-
Irregular heart rhythms
-
Organ graft rejections
-
Psychotic problems
Sour oranges, such as Seville, or their
juice, may have an effect similar to grapefruit juice. Most other citrus
fruits, such as lemons, limes, citrons, naturally sweet oranges and tangerines
are not thought to have this effect. However, tangellos, a hybrid of grapefruit,
may also interfere with drugs.
How Grapefruit
and Its Juice React with Certain Medications
There are substances in grapefruit
that can interfere with the way your body absorbs and breaks down (metabolizes)
certain drugs. This interference allows a higher amount of the drug than
usual to circulate in your bloodstream, which can occasionally result in
serious or life-threatening adverse reactions.
As little as one glass of grapefruit
juice (8 oz. or 250 mL) can cause an increased blood drug level and the
effects can last for three days or more. Therefore, even if you drink the
juice in the morning and do not take your medication until bedtime, the
level of the drug in your blood could still be affected.
The effects vary from one person
to another, from one drug to another, and from one grapefruit juice preparation
to another. This results in an unpredictable increase in blood drug level,
which in some cases can cause serious effects.
How to Minimize
Your Risk
Take the following precautions to
minimize the risk of adverse effects when consuming grapefruit or its juice:
-
If you are taking medication for any
of the conditions listed above, DO NOT drink grapefruit juice or eat grapefruit
in any form until you have talked to your doctor and your pharmacist about
the potential for an adverse reaction.
-
Avoid taking any drug with grapefruit
juice until you have talked to your doctor or pharmacist.
-
Read the labels on foods and natural
health products to make sure they do not contain grapefruit or its juice,
or Seville oranges.
-
Always report any adverse drug reaction
to your doctor or pharmacist immediately.
How the Government
of Canada is Protecting Your Health
Health Canada has issued several
communication documents to remind health care providers of possible interactions
between grapefruit and drugs. In addition, Health Canada is working with
the drug manufacturers whose products are adversely effected by grapefruit,
to ensure that the needed information is placed on the product label. A
public advisory has been issued on grapefruit and its effect on certain
drugs.
Need More
Info?
Contact your doctor or pharmacist
if you have any concerns about possible interaction between the drug you
are taking and grapefruit.
To report all adverse reactions or
drug interactions with grapefruit contact:
Adverse Reaction Information Unit
Marketed Health Products Directorate
Health Products and Food Branch
Health Canada, Tunney’s Pasture,
Locator 0201C1
Ottawa, Ontario, K1A 1B9
Telephone: (613) 957-0337 or Toll-free:
1-866-234-2345
Facsimile: (613) 957-0335 or 1-866-678-6789
or visit our website at: http://www.hc-sc.gc.ca/hpb-dgps/therapeut/
(All information below will be available
in the Web version ONLY)
Adverse reactions or drug interactions
with grapefruit can also be reported to the following Regional ADR Centres
British Columbia
BC Regional ADR Centre
c/o BC Drug and Poison
Information Centre
1081 Burrard St.
Vancouver BC V6Z 1Y6
Tel: 604-806-8625
Fax: 604-806-8262
adr@dpic.bc.ca
Ontario
Ontario Regional ADR Centre
LonDIS Drug Information Centre
London Health Sciences Centre
339 Windermere Rd.
London ON N6A 5A5
Tel: 519-663-8801
Fax: 519-663-2968
adr@lhsc.on.ca
New Brunswick, Nova Scotia, Prince
Edward Island and Newfoundland
Atlantic Regional ADR Centre
Queen Elizabeth II Health
Sciences Centre
Drug Information Centre
Rm. 2421, 1796 Summer St.
Halifax NS B3H 3A7
Tel: 902-473-7171
Fax: 902-473-8612
rxkls1@qe2-hsc.ns.ca
Saskatchewan
Sask ADR Regional Centre
Dial Access Drug Information Service
College of Pharmacy and Nutrition
University of Saskatchewan
110 Science Place
Saskatoon SK S7N 5C9
Tel: 306-966-6340 or 800-667-3425
Fax: 306-966-6377
vogt@duke.usask.ca
Québec
Québec Regional ADR Centre
Drug Information Centre
Hôpital du Sacré-Coeur
de Montréal
5400, boul. Gouin ouest
Montréal QC, H4J 1C5
Tel: 514-338-2961 or 888-265-7692
Fax: 514-338-3670
cip.hscm@sympatico.ca
Another useful source of information
is:
Ottawa Valley Regional Drug Information
Service (OVRDIS) at
http://www.powernetdesign.com/grapefruit/
Additional source of information
for health care professionals:
The Compendium of Pharmaceuticals
and specialities (CPS). Lilac Section: Clin Info-Drug Administration and
Grapefruit Juice. |
