許多人吃完藥後，都會吃些糖果或是水果來配藥，有醫學研究發現，如果吃葡萄柚，會妨礙人體分解某些藥物，導致藥物濃度過高，目前查出共有四十三種藥會有影響，嚴重者可能造成急性腎衰竭、呼吸衰竭、內出血，甚至猝死。　 　橘黃色的葡萄柚，切開來，柚香立刻飄散出來，多汁又美味，但是如果你剛吃完藥，可千萬別吃葡萄柚，有研究指出，葡萄柚會與藥物交互作用危害人體，其中， 會造成嚴重負面反應的藥物，共有四十三種，這些藥物包含常見的降膽固醇藥，抗生素和用於治療高血壓的鈣離子通道阻斷劑，以及心臟中樞神經系統藥物，如果混 著吃，吃下的一顆藥，藥物濃度相當於吃五片藥，長期下來，會導致橫紋肌溶解症和急性腎衰竭。
　　如果葡萄柚配血壓藥，劑量過 高，血壓變的太低　有可能猝死，另外像是治療心律不整的藥物，濃度太高心跳太快，也有可能導致死亡，吃果肉或是榨成汁喝都有影響，效果會持續７２小時，老 年人對藥物過量的容許度又更低，死亡風險會更大，醫師提醒平時有慢性病的患者，還是少吃葡萄柚或是柑橘類水果，比較安全。

More Drugs Cited As A Risky Mix With Grapefruit

by Helen Thompson

November 27, 2012 4:58 PM

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Grapefruit can make for a tasty addition to breakfast. But it can also interfere with some medications.

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Grapefruit sprinkled with a little sugar has just the right amount of kick for a morning meal. But when the bitter fruit is mixed with medication, things can get a bit tricky.

Compounds in grapefruit can dramatically change how some popular drugs work in the body. And the number of drugs that can have severe side effects when combined with grapefruit has more than doubled in the last four years, says a study published Monday in the Canadian Medical Association Journal.

Consuming grapefruit while taking certain drugs can produce an overdose effect. "Taking one tablet with a glass of grapefruit juice is like taking five tablets with water," says David Bailey, a pharmacologist at the Lawson Health Research Institute in London, Ontario.

Chemicals called furanocoumarins in grapefruit deactivate an enzyme in the small intestine and liver that breaks down toxins — as well as an estimated 50 percent of all drugs. When the enzyme (called 3A4 for short) isn't working right, the drugs hang around longer and circulate at higher levels in the blood than would otherwise be the case. If the levels are high enough, a person essentially overdoses.
Bailey and his colleagues pored over clinical trial data and found 85 drugs that can interact with grapefruit juice. These include cholesterol-lowering statins, such as Lipitor, immune system suppressors for transplant patients, and some common antibiotics.
Some of those drugs, when combined with grapefruit, cause small problems, such as dizziness. But the mixtures can have more serious side effects, like gastrointestinal bleeding, breathing problems or a deadly irregular heartbeat.
Between 2008 and 2012, the number of drugs that could cause serious side effects when mixed with a glass of grapefruit juice jumped from to 43 from 17.
Bailey says that there's no way to pin the trend on a particular source. The drugs treat different disorders and act on different areas of the body. "Even within a class of drugs it's very variable," says Bailey. The same goes for patient variability.
Whether a grapefruit-drug combination might be cause for concern comes down to three factors. The drugs that are taken orally, have only a small amount of the drug dose make it into the blood and are metabolized by 3A4 are more likely to cause side effects. The severity of those effects also depends on how toxic the drug is to begin with.
Pharmacist Mary Paine, of the University of North Carolina at Chapel Hill, notes that "a major, overlooked aspect of all this is that one juice does not predict all grapefruit juice." Concentrations of furanocoumarins aren't the same for every fruit or glass, so trouble isn't guaranteed.
Grapefruit isn't alone in causing problems. Seville oranges — the primary ingredient in marmalade — pomelos and limes contain the same family of disruptive compounds.
The side effects are easily preventable, however. Patients can forgo their morning grapefruit juice, or doctors can sometimes prescribe a different drug from to achieve the same results without the grapefruit risk.