Iteractions between food and medicines don’t usually get a lot of attention. The exception is grapefruit. People didn’t take grapefruit interactions seriously when they were first discovered, but decades of research have shown that they must not be ignored.
What Are the Grapefruit Interactions with Statins?
Q. I love grapefruit. I am taking simvastatin for high cholesterol, and I am not supposed to eat grapefruit or drink grapefruit juice while I am on this drug. Is there any way to control my cholesterol that won’t interfere with enjoying grapefruit?
A. If your doctor thinks you need a statin-type drug, ask her to consider fluvastatin, pravastatin or rosuvastatin (Crestor). According to the world’s expert on grapefruit interactions, David Bailey, MD, these statins are safe alternatives to atorvastatin, lovastatin or simvastatin (CMAJ, March 5, 2013). [Dr. Bailey was part of the Canadian research team that discovered grapefruit interactions with the blood pressure medicine felodipine (Lancet, Feb. 2, 1991). That study gave this field of research its start.]
The doctor might also consider pitavastatin (Livalo). This cholesterol-lowering drug does not interact with grapefruit (American Journal of Cardiovascular Drugs, 2011).
Are Grapefruit Interactions Always a Problem?
A recent study shows that drinking grapefruit juice at the same time as taking certain other statins increases their blood levels significantly (American Journal of Medicine, Jan. 2016). Levels of simvastatin and lovastatin are 260 percent higher if taken with grapefruit juice, while the level of atorvastatin is 80 percent higher. Higher levels mean greater effectiveness: LDL cholesterol levels drop by 48 percent, and so the estimated risk of heart disease plummets by 70 percent. The authors suggest that these benefits outweigh the risk of serious side effects such as muscle breakdown (rhabdomyolysis).
Understanding Grapefruit Interactions with Statin Drugs:
There is a lot of confusion around grapefruit interactions. A few years ago we received this question:
Q. I have gotten conflicting information from my doctor, a couple of pharmacists and patient information inserts about how to avoid interactions between statins and grapefruit:
- Don’t take the medication with grapefruit juice.
- Don’t have grapefruit products at the same time of day as a statin.
- It’s OK to have grapefruit products after, but not before, a statin.
- Don’t have more than 1 quart (though one said 8 oz.) of grapefruit products a day.
- Don’t have any grapefruit products at all while taking statins.
- This warning applies to other citrus products beside grapefruit.
I hope you can clarify this. I have been avoiding grapefruit (though not other citrus juice) completely and would like to be able to eat it again if it is safe to do so.
A. Certain cholesterol-lowering drugs such as atorvastatin (Lipitor), lovastatin (Mevacor) and simvastatin (Zocor) interact with compounds in grapefruit and its juice. These natural chemicals can slow the rate at which the drugs are processed by the body. This may result in a higher blood level of the drug and consequently a greater risk of side effects.
Readers Experienced Grapefruit Interactions:
Here are two stories of what can happen when a drug like atorvastatin is affected by grapefruit:
“A few weeks ago I could not get out of my chair to go to bed. I was telling my body “stand up” but my back and legs just wouldn’t respond.
“I eventually managed to lever myself up with my arms but I had considerable difficulty getting to bed. This was odd because I am in pretty good physical shape.
“About a week before this event I had bought two gallons of grapefruit juice because it was on sale and had been consuming quite a large quantity daily. I have been on atorvastatin for about 18 months.”
“I slid to the floor of my bathroom and was unable to get up. My arms and legs did not function and I lay there for eight hours until my son picked me up. I went to the hospital but no one could find an explanation. I was taking Lipitor and eating grapefruit daily.”
Only grapefruit and bitter orange (not regular oranges) contain the active compounds. The enzymes that are affected may show changed activity for more than 24 hours after a person drinks a glass of juice, so the idea that one could have grapefruit for breakfast and take a pill before bedtime is mistaken.
Some people are far more susceptible to this effect than others. We are sending you our Guide to Grapefruit Interactions for lots more information on the interaction. Other drugs that are affected by grapefruit include some anti-seizure medicines, estrogen hormones, heart and blood pressure pills and sleeping pills. Anyone who would like a copy may download an electronic PDF version from the Health Guide section of The People’s Pharmacy.