after you swallow it?

在你的身體裡發生了什麼事？

Medicine that slides down your throat can help treat a headache,

藥物物滑入你的喉嚨有助於治療頭痛

a sore back,

背痛

or a throbbing sprained ankle.

或扭傷疼痛的腳踝

But how does it get where it needs to go in the first place?

但是藥物如何到達身體所需要的地方發揮功用呢？

The answer is that it hitches a ride in your circulatory blood stream,

答案是藥物透過血液在你的身體中繞了一圈

cycling through your body in a race to do its job before it's snared by organs

在被其他用來中和的器官和分子吸收之前，藉由繞行身體

and molecules designed to neutralize

來發揮它的功能

and expel foreign substances.

並且排除外來物質

This process starts in your digestive system.

這個過程從消化系統開始

Say you swallow an ibuprofen tablet for a sore ankle.

當你因為腳踝痠疼吞下一顆布洛芬藥丸時

Within minutes, the tablet starts disintegrating in the acidic fluids of your stomach.

不到幾分鐘，這顆藥丸開始在胃酸中分解

The dissolved ibuprofen travels into the small intestine

布洛芬錠溶解的的部分進入小腸

and then across the intestinal wall into a network of blood vessels.

然後穿過小腸壁進入血管網路

These blood vessels feed into a vein,

這些血管通往靜脈

which carries the blood, and anything in it, to the liver.

將血液和其中攜帶的物質帶到肝臟

The next step is to make it through the liver.

下一步是通過肝臟

As the blood and the drug molecules in it travel through liver blood vessels,

當血液和當中的藥物分子進入肝臟時

enzymes attempt to react with the ibuprofen molecules

酶試圖要中和

to neutralize them.

布洛芬分子

The damaged ibuprofen molecules, called metabolites,

受損的布洛芬分子被稱為代謝物

may no longer be effective as painkillers.

可能已無法發揮止痛藥的功能

At this stage, most of the ibuprofen makes it through the liver unscathed.

這個時候，大部分的布洛芬都毫髮無傷地通過了肝臟

It continues its journey out of the liver,

繼續離開肝臟

through veins,

通過靜脈

into the body's circulatory system.

進入身體的循環系統

Half an hour after you swallow the pill,

在你吞下藥丸半小時後

some of the dose has already made it into the circulatory blood stream.

有些劑量已經進入循環血液當中

This blood loop travels through every limb and organ,

血液的迴路通過四肢及各個器官

including the heart, brain, kidneys, and back through the liver.

包含心臟、腦、腎，並且回到肝臟

When ibuprofen molecules encounter a location

當布洛芬分子遇到

where the body's pain response is in full swing,

身體疼痛反應劇烈的地方時

they bind to specific target molecules that are a part of that reaction.

它們就會和該部位部分特定標靶分子結合

Painkillers, like ibuprofen, block the production of compounds

像布洛芬這類的止痛藥，會阻止

that help the body transmit pain signals.

身體產生疼痛信號的化合物產生

As more drug molecules accumulate,

當更多藥物分子聚集後

the pain-cancelling affect increases,

疼痛逐漸減輕

reaching a maximum within about one or two hours.

藥物發揮最大效能大約要 1 至 2 小時

Then the body starts efficiently eliminating ibuprofen,

然後身體就會開始有效率地減少普洛芬

with the blood dose decreasing by half every two hours on average.

平均每 2 小時減少其存在血液中劑量的一半

When the ibuprofen molecules detach from their targets,

當普洛芬分子與標靶物分離時

the systemic blood stream carries them away again.

血液系統會再次將它們帶走

Back in the liver, another small fraction of the total amount of the drug

回到肝臟，藥物總量的另一小部分

gets transformed into metabolites,

會轉化為代謝物

which are eventually filtered out by the kidneys in the urine.

最後透過腎臟，由尿液排出

The loop from liver to body to kidneys continues at a rate

由肝臟經過身體到腎臟的迴路持續以

of about one blood cycle per minute,

每分鐘一次血液循環的速率進行著

with a little more of the drug neutralized and filtered out in each cycle.

每次循環，就會有多一些的藥物被中和及濾出

These basic steps are the same for any drug that you take orally,

任何口服藥物基本上都是透過這些相同的基本步驟

but the speed of the process

但是全程的速度

and the amount of medicine that makes it into your blood stream

和藥物進入血液的量

varies based on drug,

會因藥物、

person,

人，

and how it gets into the body.

以及藥物進入身體的方式而異

The dosing instructions on medicine labels can help,

藥物標籤上的劑量說明是有幫助的

but they're averages based on a sample population

但是這僅是基於樣品人口的平均值

that doesn't represent every consumer.

並不是每個人都適用

And getting the dose right is important.

使用正確的劑量是很重要的

If it's too low, the medicine won't do its job.

如果劑量過低，藥物就無法發揮作用

If it's too high, the drug and its metabolites can be toxic.

如果劑量過高，它的代謝物可能會是有毒的

That's true of any drug.

任何藥物都是這樣

One of the hardest groups of patients to get the right dosage for are children.

最難獲得正確劑量使用的就是兒童

That's because how they process medicine changes quickly, as do their bodies.

因為兒童對藥物的反應過程改變得很快，他們的身體也變得很快

For instance, the level of liver enzymes that neutralize medication

舉例來說，中和藥物的肝酶平均值

highly fluctuates during infancy and childhood.

在嬰兒和孩童時期變化很大

And that's just one of many complicating factors.

但是這只是眾多複雜因素之一

Genetics,

遣傳、

age,

年齡、

diet,

飲食、

disease,

疾病，

and even pregnancy influence the body's efficiency of processing medicine.

甚至懷孕都會影響身體對藥物反應過程的效率

Some day, routine DNA tests may be able to dial in the precise dose of medicine

有時候，一般的 DNA 測試也許能夠依據肝臟效能和其他因素

personalized to your liver efficiency and other factors,

調整個人化的精確劑量

but in the meantime,

但是同時

your best bet is reading the label

你最好還是閱讀藥物標籤

or consulting your doctor or pharmacist,

或諮詢醫師或藥劑師

and taking the recommended amounts with the recommended timing.

並在適合的時間服用適當的劑量