Grapefruit? What’s the Problem?
The other day I found myself with a grapefruit in my hand and an old wives tale in my head. I don’t know why it came to me, but something was telling me not to eat the Grapefruit; something about grapefruit making the pill not work, like St John’s wort?
Then I doubted myself. How can a grapefruit be an evil kind of citrus when all the rest are fine?
What was I going to do with the Grapefruit tree in my back yard, plumb and ladened with the most burdensome of citrus? I started to ask a few friends if they had heard of this medication mixing myth.
I Started to Hear Conflicting Stories –
- A friend of mine told me her mother could not drink Grapefruit juice while she was being treated for Breast Cancer – Apparently the nurses where quite insistent.
- Another friend told me to eat plenty of Grapefruit as it is listed as a great food to eat on the alkaline diet, with mangos, limes, lemons and papaya.
- ‘Grapefruits? Oh yes, you should eat one every day – Very good for the fat burning’ they told me.
- ‘Grapefruit? Oh no! Stay away from that one.
My current contraceptive pill warns me to stay away from St John’s Wart, but there is not mention of Grapefruit on the instructions –
Is it just an old wives tale?
I decided to find out weather or not the humble fat busting little sour drum could really cause that much damage. I had to do some research.
I googled ‘Grapefruit and Medications’ Wow!
There is a lot of information out there to confirm that Grapefruits do in fact effect a lot of prescription medications.
‘Today, more than 30 commonly prescribed drugs carry a warning against mixing their use and grapefruits or grapefruit juice. This is not innocuous, because so many Americans have grapefruit for breakfast at a time when they also take their medications.'(1)
Here is the confusing part – Grapefruits do not interact with every drug.
Reactions between Grapefruit and prescription drugs was first documented in 1989 by a Canadian Medical Scientist,who discovered that when he took felodipine with grapefruit juice his blood-concentration of the drug was four times as high as it should have been. In other words, a standard dose combined with grapefruit juice was four times as potent as it was without grapefruit juice. (2)
‘Grapefruit juice blocks special enzymes in the wall of the small intestine that actually destroys many medications and prevents their absorption into the body. Thus, smaller amounts of the drugs get into the body than are ingested. When the action of this enzyme is blocked, more of the drugs get into the body and the blood levels of these medications increase. This can lead to toxic side effects from the medications.’ (3)
What I found was that grapefruits seem to have the most disastrous effects on the drugs that people would probably keep quite private. Drugs and medications used to treat mental health are the most susceptible to the enzyme dissolving grapefruit juice. You just never know what people are taking…
What about other citrus?
Well it looks like it is just Grapefruits. There is an emzyme in grapefruits that are not found in any other fruit at all. Weird. but true.
The truth is that Grapefruits might not have any effect on the medications and drug you are taking – But really? they aren’t that nice. I am going to just steer clear I think.
Other Medication-Effecting Foods
While researching I found this list that outlines others foods that may also effect medication and prescription drugs – Please note that this is only a small sample of medication-effecting foods and should not be taken as the only risk.
Grapefruit juice: Some statin drugs to lower cholesterol, such as simvastatin (Zocor), atorvastatin (Lipitor), and pravastatin (Pravachol); some blood pressure-lowering drugs, such as Nifediac and Afeditab ; some organ transplant rejection drugs, such as Sandimmune and Neoral (both cyclosporine); some anti-anxiety drugs, such as BuSpar (buspirone); some anti-arrhythmia drugs, such as Cordarone and Nexterone (both amiodarone); some antihistamines, such as Allegra (fexofenadine); the anti-malaria drugs Quinerva or Quinite (quinine); and Halcion (triazolam), a medication used to treat insomnia.
Licorice: The sweetening compound glycyrrhizin in black licorice may reduce the effects of some blood pressure drugs or urine-producing drugs including Hydrodiuril (hydrochlorothiazide) and Aldactone (spironolactone). It may increase the toxicity risks from Lanoxin (digoxin), used to treat congestive heart failure and abnormal heart rhythms.
Chocolate: Antidepressant Monoamine Oxidase (MAO) inhibitors (such as phenelzine (Nardil, Nardelzine) and tranylcypromine (Parnate) are just one category of drugs that shouldn’t be consumed with excessive amounts of chocolate and other caffeinated foods. Caffeine can also interact with stimulant drugs such as Ritalin (methylphenidate), increasing their effect, or by decreasing the effect of sedative-hypnotics such as Ambien (zolpidem). Using bronchodilators with caffeinated foods and drinks can increase the chance of side effects, such as excitability, nervousness, and rapid heart beat.
Potassium-rich foods (such as bananas, oranges, and green leafy vegetables): Can add to high potassium levels in the body caused by ACE (Angiotensin Converting Enzyme) inhibitors including captopril (Capoten) and enalapril (Vasotec) prescribed to lower blood pressure or treat heart failure. Too much potassium can cause an irregular heartbeat and heart palpitations.
St. John’s Wort (Hypericum perforatum): Can reduce concentrations of medications in the blood, including digoxin (Lanoxin), used to treat congestive heart failure and abnormal heart rhythms; the cholesterol-lowering drug lovastatin (Mevacor and Altocor), and the erectile dysfunction drug sildenafil (Viagra).
Vitamin E: Taken with a blood-thinning medication such as warfarin (Coumadin) can increase anti-clotting activity and may cause an increased risk of bleeding.
Ginseng: May increase the risk of bleeding when taken with anticoagulants (blood thinners such as warfarin and heparin). Can also increase the bleeding effects of aspirin and non-steroidal anti-inflammatory drugs such as ibuprofen, naproxen, and ketoprofen. Combined with MAO inhibitors such as Nardil or Parnate may cause headache, trouble sleeping, nervousness and hyperactivity.
Ginkgo biloba: High doses can decrease the effectiveness of anticonvulsant therapy in patients taking seizure-control medicines Tegretol, Equetro or Carbatrol (carbamazepine), and Depakote (valproic acid). (4)
Grapefruit and Prescription Drugs: Mix Carefully – By Mark Bloom HealthDay Reporter, (1)(2)
Grapefruit Juice Can Interact With Medicines! – Original Medical Author: William C. Shiel, Jr, MD, FACP, FACR Medical Editor: Jay W. Marks, MD, (3)
Grapefruit not only food that can Effect Medication – Michelle Healy, USA TODAY (4)