Orange and grapefruit juices are great sources of potassium and vitamin C, but some of you said you shy away from grapefruit — not because you don't love the taste, but because it interferes with the effectiveness of certain medications. It's true. There are chemical compounds in grapefruit known as furanocoumarins (FCs) that affect the enzymes in the intestines and liver that break down meds.
There's a list of drugs that doctors insist you avoid grapefruit and grapefruit juice while taking, because it can cause dangerously high levels of the drug in the blood, which can lead to serious side effects. Pomelos and Seville oranges, a type of bitter orange often used to make marmalade, should also be avoided.
To see a list from the Mayo Clinic of which meds may be affected by grapefruit, keep reading.
- Amiodarone (Cordarone): used to treat and prevent abnormal heart rhythms
- Buspirone (BuSpar), sertraline (Zoloft): used to treat depression and anxiety
- Carbamazepine (Carbatrol, Tegretol): anti-seizure medication
- Cyclosporine (Neoral, Sandimmune), tacrolimus (Prograf): immunosuppressant drugs used after organ transplants, or to treat autoimmune diseases such as Chrohn's disease, or non-autoimmune inflammatory diseases such as asthma
- Felodipine (Plendil), nifedipine (Procardia), nimodipine (Nimotop), nisoldipine (Sular): used to treat high blood pressure
- Saquinavir: used to treat HIV
- Simvastatin (Zocor), lovastatin (Mevacor), atorvastatin (Lipitor): used to treat high cholesterol
Do you take any of these meds? Did you know that citrus could be a problem?
Francesco Biasia
melissa
Tibi
I've heard stories of grapefruit juice affecting the effectiveness of birth control pills. Is there any light you can shed on this for me?
1you missed alprazolam
2Yes, grapefruit/grapefruit juice can affects BC, but if you eat or drink it hours before you take it, it would be fine.
Example: Drink grapefruit juice in the morning and take your BC at night or eat grapefruit at 6pm and take your BC at say at 9pm you will be fine.
Your BMI can also affect your BC too. The higher (30+, if I remember right) it is the more quickly your body breaks it down.
3Probably should have also mention eat/drinking grapefruit/ grapefruit juice hours before taking any medication(s) affected by it would be fine. At least you take two medications that are affect by it...one in the morning and the other in the evening than that would be different.
4I learned of this interaction a few years back. I am an absolute grapefruit fiend, so I always ask a prescribing doctor if eating the fruit or drinking the juice will cause problems. If it does, I ask if something else non-reactive can be prescribed instead.
5I knew about the grapefruit juice effect, but since I'm not on any of those meds, I never really thought about it too much. Plus, I barely ever drink grapefruit juice or eat grapefruits, so I guess I never really gave it much thought.
6Left out a big one... Budesonide (Entocort EC). A synthetic corticosteroid for people who have Chron's or ulcerative colitis.
7Actually, the FCs in grapefruit affect the intestinal enzymes for a full 24 hours. That is why doctors recommend avoiding grapefruit and grapefruit juice altogether when taking these medications. So even if you eat grapefruit in the morning and take one of these medications in the evening you'll still get the effect of your medication being intensified.
Chemically speaking, these intestinal enzymes downregulate the activity of the drugs listed. Drug companies are aware of this and calibrate the strength of their drugs accordingly. The FCs in grapefruit *inhibit* the intestinal enzymes, meaning that you will now get a dosage of your medication in an amount greater than the drug manufacturer intended--which can be dangerous, and the reason grapefruits should be avoided altogether with these medications.
8To clear a couple things up...
Grapefruit juice does NOT decrease the effectiveness of birth control pills.
The isoflavones in grapefruit juice are metabolized by a certain type of liver enzyme (CYP3A4). This liver enzyme is also responsibe for the metabolism of about 75% of the drugs on the market. Concurrent ingestion of grapefruit juice and CYP3A4 drugs causes the enzyme to become overloaded - slowing the metabolism of both isoflavones and drugs. This isn't such an issue if the drug has other metabolic routes for elimination (via other enzymes or via other organs) or if the drug is fairly safe. It becomes problematic if the drug heavily relies on CYP3A4 and is highly toxic (such as the ones on the Mayo Clinic's list).
If you are taking a drug that is on that list, you should avoid grapefruit juice altogether. Spacing out the med from the juice doesn't make a difference since if you regularly consume grapefruit juice, the interaction will always be there.
- a pharmacist
9I didn't believe it until I heard my local hospital stopped serving it as it was causing problems!
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