评论
打印
Have you ever wondered what happens to a painkiller, like ibuprofen, after you swallow it?
你可曾想过一片止痛药，如布洛芬，被你吞下以后会发生什么事情吗？
Medicine that slides down your throat can help treat a headache, a sore back, or a throbbing sprained ankle.
你吞下的药物可以治疗头痛、背疼，或者还在隐隐作痛扭伤了的踝关节。
But how does it get where it needs to go in the first place?
但它是怎样在第一时间就到达它需要前往的地方呢？
The answer is that it hitches a ride in your circulatory blood stream,
答案就是它会搭上你血液循环的便车，
cycling through your body in a race to do its job before it's snared by organs and molecules designed to neutralize and expel foreign substances.
在它被身体器官和能够中和和驱除外来物质的特定分子捕捉到之前，在你身体里流通的时候赶紧去完成它的工作。
This process starts in your digestive system.
这个过程发生在你的消化系统中。
Say you swallow an ibuprofen tablet for a sore ankle.
设想你关节疼痛，因此你吞下了一枚布洛芬片。
Within minutes, the tablet starts disintegrating in the acidic fluids of your stomach.
几分钟内，药片开始在你胃部的酸性液体中分解。
The dissolved ibuprofen travels into the small intestine
溶解了的布洛芬片会来到小肠，
and then across the intestinal wall into a network of blood vessels.
然后穿过小肠璧进入血管网络。
These blood vessels feed into a vein, which carries the blood, and anything in it, to the liver.
这些血管会汇入静脉，静脉会运送血液和血液中含有的任何物质到肝脏。
The next step is to make it through the liver.
下一步就是让它通过肝脏。
As the blood and the drug molecules in it travel through liver blood vessels,
血液和药物分子流经肝脏血管的时候，
enzymes attempt to react with the ibuprofen molecules to neutralize them.
酶会跟布洛芬分子发生反应来中和它们。
The damaged ibuprofen molecules, called metabolites, may no longer be effective as painkillers.
被破坏的布洛芬分子，亦称代谢物，或许不能再起到止痛片的作用了。
At this stage, most of the ibuprofen makes it through the liver unscathed.
在这一阶段，绝大多数布洛芬会让自己在免受伤害的情况下穿过肝脏。
It continues its journey out of the liver, through veins, into the body's circulatory system.
离开肝脏之后它继续自己的旅程，流经静脉，进入人体的循环系统。
Half an hour after you swallow the pill, some of the dose has already made it into the circulatory blood stream.
在你吞下药片的半小时后，部分剂量已经参与到血液循环过程。
This blood loop travels through every limb and organ, including the heart, brain, kidneys, and back through the liver.
这种血液循环会流经四肢和人体器官，包括心脏、大脑和肾脏，然后回到肝脏。
When ibuprofen molecules encounter a location where the body's pain response is in full swing,
当布洛芬分子遇到一个地方正发出身体疼痛的强烈信号，
they bind to specific target molecules that are a part of that reaction.
它们会跟能引起化学反应的特定靶分子结合。
Painkillers, like ibuprofen, block the production of compounds that help the body transmit pain signals.
止痛片像布洛芬会限制化合物的产生，这些化合物会帮助人体传递疼痛信号。
As more drug molecules accumulate, the pain-cancelling affect increases, reaching a maximum within about one or two hours.
药物分子积聚得越多，减轻疼痛的效果就越显著，大概在一至两小时内会达到最大值。
Then the body starts efficiently eliminating ibuprofen, with the blood dose decreasing by half every two hours on average.
然后身体开始高效消除布洛芬，平均每两个小时血液中的药物剂量就会减半。
When the ibuprofen molecules detach from their targets, the systemic blood stream carries them away again.
当布洛芬分子从靶分子中分离出来，血液循环系统会再次把它们运载出去。
Back in the liver, another small fraction of the total amount of the drug gets transformed into metabolites,
回到肝脏，而药物中的另一小部分会转化为代谢物，
which are eventually filtered out by the kidneys in the urine.
这些代谢物最终会被肾脏过滤掉而后变成尿液。
The loop from liver to body to kidneys continues at a rate of about one blood cycle per minute,
从肝脏到人体再到肾脏的血液循环速率大概是每分钟一次，
with a little more of the drug neutralized and filtered out in each cycle.
每次循环就会有更多的药物被中和和过滤掉。
These basic steps are the same for any drug that you take orally,
无论你口服什么药物，这些基本步骤都是会发生的，
but the speed of the process and the amount of medicine that makes it into your blood stream
只是过程的速率和进入你血液循环的药物剂量会
varies based on drug, person, and how it gets into the body.
因药物种类、不同的人以及如何进入人体体内而有所差异。
The dosing instructions on medicine labels can help,
药物标签上的剂量介绍能给你提供帮助，
but they're averages based on a sample population that doesn't represent every consumer.
但它们只是取了样本人口的平均值，并不代表每一位消费者。
And getting the dose right is important.
而摄取正确的剂量是很重要的。
If it's too low, the medicine won't do its job.
如果剂量太低，药物起不了作用。
If it's too high, the drug and its metabolites can be toxic. That's true of any drug.
如果剂量太高，药物产生的代谢物可能会有毒性。这是对任何药物都适用的道理。
One of the hardest groups of patients to get the right dosage for are children.
最难摄取到正确剂量的群体之一就是儿童。
That's because how they process medicine changes quickly, as do their bodies.
因为他们的身体处理药物的过程变化得太快了。
For instance, the level of liver enzymes that neutralize medication highly fluctuates during infancy and childhood.
例如中和药物的肝脏酶水平，在婴儿和儿童时期波动起伏很大。
And that's just one of many complicating factors.
而这只是众多复杂因素中的一种。
Genetics, age, diet, disease, and even pregnancy influence the body's efficiency of processing medicine.
遗传、年龄、饮食、疾病，甚至是怀孕期都会影响身体处理药物的效率。
Some day, routine DNA tests may be able to dial in the precise dose of medicine personalized to your liver efficiency and other factors,
或许有一天常规的DNA测试可以根据你肝脏功能效率和其他因素测量药物的精确剂量，
but in the meantime, your best bet is reading the label or consulting your doctor or pharmacist,
但与此同时，你最好的选择就是阅读药物标签，或者咨询你的医生或者药剂师，
and taking the recommended amounts with the recommended timing.
然后在建议的时间内服用推荐剂量。
