1. Drug - Food Interactions

2. Nutritional Values Of Grapefruit
Grapefruit is a citrus fruit rich
in the following nutrients:
Vitamin C
Vitamin A
Vitamin B5
Potassium
Folate
Dietary Fiber

3. Nutritional Values Of Grapefruit
The nutritional values of
grapefruit varies with the
color (white, pink, or red).
Red and pink grapefruits
have a higher amount of
vitamin A. 

4. Medical Uses Of Grapefruit
Grapefruit is an excellent source of Vitamin C
which plays a role in the following:
Supporting the immune system
Reduce severity of cold symptoms
Reduce severity of inflammatory conditions
Is beneficial to promoting cardiovascular health
Pink and Red Grapefruit appears to have
anti-tumor activity.

5. Interactions Of Grapefruit With Medications
What Is Interaction?
It is a situation in which a substance affects
the activity of the used medication by one
of the following ways:
The effect is increased.
The effect is decreased.
It produces a new effect.

6. How Does Grapefruit Interact
When we take a medicine
orally (by mouth), it has to
get into our blood stream to
do its action.
During this a significant portion of
the medicine is metabolized(changed)
to inactive ingredients by a certain
enzyme in either the intestine (first-pass metabolism) or the
liver,decreasing the amount of medication reaching the Blood.

7. How Does Grapefruit Interact
Grapefruit juice interferes with the
enzyme system responsible for
the metabolism of many
medications.
Therefore, the amount of
medication available in the body
will increase, possibly causing
toxic effects.

8. How Long Dose Grapefruit Interaction Persist
Grapefruit juice can inhibit intestinal
enzyme concentration for 24 to 72
hours.
Therefore, separating the times of
medication administration and
grapefruit consumption is not a
reasonable solution.
It is important to note that
because of genetic differences,
the extent of interaction differs
from one patient to another.

9. Grapefruit and Statins
Statins are medications that lower cholesterol levels
by blocking the enzyme responsible for cholesterol
synthesis in the body.
Statins are the most widely
prescribed cholesterol
lowering medications,
since they affect every aspect in
the cholesterol panel in a favorable way.

10. Grapefruit and Statins
The components in grapefruit prevent the enzyme
system in the body from breaking down the statin
leading to its accumulation in the body.
Example:
Taking one tablet of lovastatin (Mevacor)
with a glass of grapefruit juice
is the same as taking 12 to 15 tablets
with a glass of water.

11. Problems Of Taking Grapefruit With Statins
Problems associated with taking grapefruit with
stains are:
Liver damage
Kidney damage
Rhabdomyolisis
This rare but potentially life-threatening
Side effect. The most common symptoms are:
Severe muscle aching throughout the
entire body
Muscle weakness
Dark or cola-colored urine
The higher the dose of statins, the higher the risk of
Rhabdomyolysis.

12. Are All Statins Affected
So far, the only statins significantly affected by this interaction
are:
Atorvastatin (Lipitor®)
Lovastatin (Mevacor®)
Simvastatin (Zocor®)
Other statins do not seem to demonstrate
the same, profound effect with grapefruit
as seen with the other statins. These would include:
Rosuvastatin (Crestor®)
Pravastatin (Pravachol ®)
Fluvastatin (Lescol ®)
This may be due to the fact that these statins are not broken
down by the same enzymes.

13. Grapefruit And Antihistamines
Antihistamines are medications used to treat allergies.
Interaction of grapefruit with antihistamines
like terfenadine or astemizole leads to fatal
cardiac arrhythmias (Irregular heart beat).
There are other non-sedating antihistamines which do not
interact with grapefruit juice. (e.g., loratidine (Claritin ®)
cetirizine (Zyrtec ®).

14. Grapefruit and Calcium Channel Blockers
Calcium Channel Blockers are medications that prevent
calcium from entering cells of the heart and blood vessel
walls, resulting in lowering blood pressure.
Grapefruit juice is likely to increase the levels of Calcium
Channel Blockers in the blood causing the following:
Low blood pressure
Increased heart rate
Dizziness
Flushing
Headache

15. Other Medications Affected By Grapefruit
Grapefruit interacts with a wide range of medications such as:
Psychiatric Medications
Immune Suppressants
Pain Medications (Methadone)
Impotence drugs
Intestinal Medications (Cisapride)
Grapefruit juice inhibits the body's ability to absorb some
drugs like: 
Losartan (for lowering blood pressure)
Digoxin (for treating congestive heart failure)

16. Grapefruit Forms Will all forms of grapefruit cause
interaction with medications
It has been shown that both
grapefruit sections and grapefruit
extract has the same effect on
medications as grapefruit juice.

17. Grapefruit And Citrus Fruits
There are citrus fruits which
can cause the same drug
interaction as grapefruit
such as:
Seville Orange (found in marmalade and jams)
Pomelos
Tangelos

18. What Are Pomelos Pomelo - Also called the "Chinese
grapefruit", it's native to southeast
Asia.
It is, in fact, an ancestor of the
grapefruit.
The grapefruit was formed from
crossing between the pomelo and
the orange to give us the modern
grapefruit varieties we know
today.

19. What Are Tangelos The tangelo is a hybrid between the pomelo and the
tangerine.
The fruit is known in some
countries as "sweetie”.

20. Summary A number of medications are reported to have
interactions with grapefruit.
Before taking any
medication with grapefruit
you have to make sure that
there is no interaction.
There are several other fruit
juices available as a
substitute to grapefruit juice.