Eating grapefruit or consuming other grapefruit products while taking simvastatin to lower your cholesterol can lead to serious and dangerous side effects. Grapefruit interferes with an enzyme in the intestine that helps break down simvastatin and many other drugs. This can lead to dangerous levels of simvastatin staying in your system, increasing the risk and severity of side effects.
Effects
Eating grapefruit or consuming grapefruit juice while taking simvastatin increases the amount of the drug in your bloodstream by up to 12 times, explains eMedTV. This increase can cause muscle problems that interfere with your kidneys. In rare and severe cases, your kidneys shut down completely. Contact your doctor or an emergency medical facility if you accidentally ingest large quantities of grapefruit or grapefruit juice or if you experience any severe symptoms, including muscle pain or weakness, unusual fatigue, jaundice, pain with urination, dark urine or a significant decrease in urination.
Time Frame
The enzyme in grapefruit that interacts with simvastatin can stay in your system for several hours or even days. In some cases, traces of the enzyme are detected for up to two days after consumption. Don't drink grapefruit juice in the morning and take your medication later in the day thinking the fruit is out of your system.
Considerations
Some people are more sensitive to the effects of grapefruit than others. You might be able to enjoy a few bites of grapefruit as a rare treat if you take simvastatin, but don't indulge without checking with your doctor. In rare cases, your doctor might advise you to eat grapefruit or drink grapefruit juice with your medication in an effort to lower the dosage. This combination is very experimental, however, and you should not try it without your doctor monitoring you closely. If you truly can't stand the thought of giving up grapefruit, talk to your doctor about alternative cholesterol-lowering medications that do not interact with grapefruit, such as fluvastatin or pravastatin.
Alternatives
If you can't take another drug for your cholesterol, and you truly enjoy grapefruit or grapefruit juice, try substituting with other citrus fruits or juices. Most fruits do not react with medications the way grapefruit does, so oranges, limes, tangerines and lemons are all safe to eat. Seville oranges, also called bitter oranges, react with simvastatin in the same manner as grapefruit, so don't include those on your list of substitutes.
