How does your body process medicine? - Céline Valéry

譯者: 舒婷 楊 審譯者: Ann Chen

Have you ever wondered what happens to a painkiller, like ibuprofen,

你是否曾想過 當你吞下止痛藥，像是布洛芬

after you swallow it?

它會發生什麼變化呢？

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

從喉嚨滑下的藥物 會幫你治療頭痛

a sore back,

背痛

or a throbbing sprained ankle.

或腳踝扭傷的抽痛

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

但首先它是如何到達 需要去的地方呢？

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

答案是藥物會藉由循環血流的運送

cycling through your body in a race to do its job

在體內循環並快速發揮作用

before it's snared by organs and molecules designed to neutralize

直到被器官攫取 且分子被分解失效

and expel foreign substances.

然後把外來物排出

This process starts in your digestive system.

這個過程始於你的消化系統

Say you swallow an ibuprofen tablet for a sore ankle.

當你因為腳踝痠痛吞下布洛芬錠

Within minutes, the tablet starts disintegrating in the acidic fluids

幾分鐘內藥物開始被胃中的胃酸分解

of your stomach.

The dissolved ibuprofen travels into the small intestine

被溶解的布洛芬進入小腸

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

然後通過腸壁進入血管網絡

These blood vessels feed into a vein,

這些血管注入一條靜脈（肝門靜脈）

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

它運送血液及其內含物進入肝臟

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,

當血液和藥物分子行經肝臟血管

enzymes attempt to react with the ibuprofen molecules

酵素會試圖與布洛芬產生反應

to neutralize them.

使之失去作用

The damaged ibuprofen molecules, called metabolites,

損壞的布洛芬分子稱為「代謝物」

may no longer be effective as painkillers.

就不再具有止痛藥的作用

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

在此階段，大部分的布洛芬 都能安然通過肝臟

It continues its journey out of the liver,

它會經由靜脈繼續離開肝臟

through veins,

into the body's circulatory system.

進入身體的循環系統

Half an hour after you swallow the pill,

在你吞下藥物的半小時後

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

一些藥物已經進入循環血流內

This blood loop travels through every limb and organ,

這些血液管路通過四肢和器官

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

包括心臟、腦、腎臟 然後返回肝臟

When ibuprofen molecules encounter a location

當布洛芬分子來到 身體疼痛非常強烈的地方

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

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

它們會與反應中的特定目標分子結合

Painkillers, like ibuprofen, block the production of compounds

像布洛芬的止痛藥會阻斷

協助傳送疼痛訊號的複合物之製造

that help the body transmit pain signals.

As more drug molecules accumulate,

當越多藥物分子積聚

the pain-cancelling affect increases,

止痛的藥效也會隨之增加

reaching a maximum within about one or two hours.

一到兩小時內會達到最大的效果

Then the body starts efficiently eliminating ibuprofen,

然後，身體開始有效率地清除布洛芬

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

平均每兩小時 血中藥的濃度減半

When the ibuprofen molecules detach from their targets,

當布洛芬分子與特定目標分子分離

the systemic blood stream carries them away again.

血液系統也會再次將布洛芬分子帶走

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

回到肝臟後 又有藥物總量的一小部分

gets transformed into metabolites,

被轉換成代謝物

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

最後由腎臟濾出到尿液

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

從肝到身體到腎的環路 以約每分鐘血循環一次的速度進行

of about one blood cycle per minute,

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

每次循環就有部分藥物 被分解失效且排出

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

任何口服藥物都是同樣的循環方式

but the speed of the process

但其運作的速度

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

以及進入血液的藥物劑量

varies based on drug,

則會因為藥物

person,

人

and how it gets into the body.

和進入身體的方式而不同

The dosing instructions on medicine labels can help,

藥物標籤上的劑量指示會有助益

but they're averages based on a sample population

但它們通常是以 抽樣人口的平均值為基準

that doesn't represent every consumer.

並非每位使用者均適用

And getting the dose right is important.

使用正確的藥物劑量很重要

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

劑量太低，藥物不會發揮功效

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

劑量太高，藥物及其代謝物是有害的

That's true of any drug.

任何藥物都是如此

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

最難掌控正確劑量的 病人群之一是小孩

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

那是因為他們處理藥物變化迅速 正如他們身體一樣

For instance, the level of liver enzymes that neutralize medication

例如，代謝藥物的肝臟酵素濃度

highly fluctuates during infancy and childhood.

在嬰幼兒時期起伏很大

And that's just one of many complicating factors.

這只是許多複雜原因的其中之一

Genetics,

基因

age,

年齡

diet,

disease,

飲食習慣

疾病

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

甚至懷孕都會影響代謝藥物的效率

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

未來，或許例行基因檢測 能依個人肝臟效能與其他因素

personalized to your liver efficiency and other factors,

而精準算出藥物使用劑量

but in the meantime,

但在此其間

your best bet is reading the label

最好還是詳閱藥物的標籤

or consulting your doctor or pharmacist,

或者詢問你的醫師或藥師

and taking the recommended amounts with the recommended timing.

在對的時間用適當劑量的藥物