Saturday, December 31, 2011

Enjoy Grapefruit with Your Statin

Do you worry about grapefruit? This is not a strange question if you take a statin. 
I say: enjoy grapefruit with your statin.

Do you take a statin? Do you like grapefruit or grapefruit juice? Then read on.

There are 7 statins on the market. They all lower the LDL cholesterol and are prescribed to reduce the risk of cardiovascular disease. These statins are listed below with the brand name in the U.S. given in parentheses:
·      atorvastatin (Lipitor)
·      fluvastatin (Lescol),
·      lovastatin (Mevacor)
·      pitavastatin (Livalo)
·      pravastatin (Pravachol)
·      rosuvastatin (Crestor)
·      simvastatin (Zocor)

If you take a statin, you may have seen warnings or alerts about eating grapefruit or drinking grapefruit juice. Those warnings imply that drinking grapefruit juice anytime during the day even hours apart from when you take your statin may be deadly.

These alerts are almost everywhere. And I believe they are way overblown and not based upon sufficient scientific or clinical evidence.

Only three of the above statins have warnings regarding eating grapefruit or drinking grapefruit juice while taking the statin. Those 3 statins are: atorvastatin (Lipitor), lovastatin, and simvastatin.

The official prescribing information for these 3 statins cautions about drinking more than a quart a day of the grapefruit juice. 
Wow that’s  a lot! There are not going to be too many people doing that.

But what if you’re a little weird and do drink more than a quart a day of grapefruit juice and  also take atorvastatin which is now available as a generic? Or, what if you love grapefruit and eat 3 a day and also take simvastatin?

How risky is this?

Well it turns out that this whole issue might be important but it is probably very much exaggerated.
Or to put it another way it is likely clinically insignificant.

The chemical components in many foods affect how our body handles or processes the chemical molecules in drugs. Grapefruit is one of those foods that contain substances that affect how are body processes some of the statins.

The liver and kidneys are the main organs that metabolize, breakdown, process or eliminate the chemicals in drugs and the many chemicals that make up our foods. Remember food is composed of chemical molecules too.

Food is digested in our small intestines. And substances that make up our food get into the bloodstream from our intestines.

Well, it turns out that besides the kidneys and liver, our intestines also change and process chemical substances from our medications. The intestines are not just for digestion. They also process chemical molecules.

Grapefruit juice has substances that affect how the intestines process many drugs. 
Those effects vary between people.
And these effects of grapefruit are also difficult to predict and very complicated.

It appears that some substances, called furanocoumarins, in grapefruit juice may reduce intestinal CYP3A4 an enzyme that breaks down many drugs.
Grapefruit may also reduce uptake into the bloodstream of substances by acting on OATP1A2, a transporter protein.

And last, grapefruit may affect blood levels of drugs by affecting a substance called P-glycoprotein. P-glycoprotein helps the body eliminate drugs from cells.

Most of the scary alerts about grapefruit and statins arose because of a study done out of one center in Finland. That study used a 60 milligram dose of simvastatin which is now above the recommended maximal dose of 40 milligrams. In addition, that study had the 10 volunteers drink 200 milliliters of double strength grapefruit juice three times a day. That amount of grapefruit juice is equivalent to about 40 ounces or 1 and ¼ quarts of single strength grapefruit juice daily!

In this study there was an increase in the blood level of simvastatin. The study was conducted over only 2 days.

Another, more recent study conducted by these same researchers also showed an increase in blood levels of simvastatin but the volunteers in this 3 day study drank only only 200 milliliter (about 7 ounces). The amount (expressed as area under the curve and peak concentration) of the simvastatin was increased on average about 3-4 times above the usual.

And when the simvastatin is taken24 hours after high dose grapefruit juice, no meaningful increase in simvastatin levels were seen.

The concern is that there may be an increased risk of muscle damage with the high blood levels of the statin. Muscle damage or myopathy is the only real risk of statin use.

Rhabdomyolysis is a severe form of muscle damage. Rhabdomyolysis is rare.
Rhabdomyolysis occurs in less than 2 persons out of 100,000 who take statins for a year.
Doctors can reduce the chances of a patient getting rhabdomyolysis by understanding  factors that increase risk.

 No clinical reports of problems have been described in humans when grapefruit juice is taken with statins.

And remember, this is primarily a possible issue with simvastatin and lovastatin
In a recent study, daily drinking of grapefruit juice did not have a significant effect on drug levels of atorvastatin despite the official prescribing information

Grapefruit juice should be an important concern in those people on immuno-suppressants, those on chemotherapy and those on drugs for HIV infection.

There are also certain medications that you might be taking that could increase your risk of statin myopathy whether you drink grapefruit juice or not.
Your doctor should know about those and take one of three steps:
reduce your statin dose or change you to a safer statin or change the other medication.

For most people,  you can enjoy grapefruit with your statin.
Check with your doctor if you have questions. And direct him to this post if he is not sure.

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