让基因药物测试走进加国百姓人家 04-13

 

当我向我的家庭医生报告说我只服用了他给我开的缓解焦虑症药物之剂量的一半时，他显出一脸的不悦，并告诉我说这个剂量下药物根本不起作用。

When I told my family doctor that I was taking just half the dose of the medication he prescribed for my anxiety disorder, he didn’t like it, telling me that at such a low dose, it would render the drug ineffective.

他说道：“你认为的作用只不过是心理作用罢了！这个剂量根本没能触及你的神经系统。”

“It was the only placebo effect that makes you believe it was working… It actually didn’t touch you at all,” he told me. 

但我知道这个剂量的药物的确起了作用，它帮我缓解了压力，放松了紧张的神经，同时将副作用降到最低水平。但获得这一结论并非轻而易举。在我遵循医嘱，按剂服药之初，从心跳过速，头昏和极度疲乏等一系列过量服药的副作用让我痛苦不堪，让极易感到焦虑和紧张的我倍感不适。有很多次我都想放弃用药，另寻良医。

But I knew that at that dosage, the drug has helped lower my stress level, allowing me to feel relaxed while showing minimum side effects. But I didn’t come to this finding without price. When I tried the prescribe dosage by following my doc’s order, terrible symptoms of overdose -- from racing heartbeat to dizziness to fatigue – had taken a heavy toll on my predisposed vulnerability to anxiety and stress, leading to my repeated attempts to quit the drug altogether. 

但我白人医生的话语让我既困惑又难解。“为什么让别人根本不管用的剂量却在我身上起了作用？”“是不是所有药物都会像这种药物一样在我身上起作用？”“是不是他将来给我开的正常剂量的药物都会让我有过量服药的感觉？”

But my Caucasian doctors’ words only made me more frustrated and confused. “Why did the dose that won’t work on others made me respond to it?” Do I respond to all drugs in a similar way? Would I experience drug overdose if I follow my doctors’ orders for other drugs he would prescribe in future?”

事实上，人类个体对药物的反应都存在差异，而每人对药物的反应都是由个体携带的基因组合决定的。虽然有些人可以一天用酒水送服用10种不同药物而丝毫不动声色，另一些人服用抗菌素就会产生便体红疹等全身反应。

The fact is that individual human beings react to drugs differently and that a set of specific genes shape a person’s response to medications. While somebody who takes 10 medicine a day, throws them back with a glass of wine and just be okay, others broke out in a full-body rash in response to antibiotic to stave off infection.

慢速药物代谢者都会携带使某种阻止药物转换成有效成分之基因变种，而快速吸收药物者则会很快分解药物成分并将其迅速排出体外。 因此，对一名快速药物代谢者不太有效甚至完全不起作用的药物剂量却会让一名慢速代谢者药物中毒甚至面临生命危险。

A poor metabolizer of certain drugs carries gene variants that hamper their ability to covert the drugs to its active form, while a rapid metabolizer would break down the drug too quickly and get it eliminated from their system at a faster speed. As such, a poor metallizer may face increased intoxication even life-threatening risks for taking a dosage that would render it less effective or even useless at all to a rapid metabolizer.

族裔因素在人类药物吸收，代谢方面起着非同凡响的作用。作为人类最早的种族，非洲后裔通常需要比亚裔和白人服用更高药物剂量，因为他们的肝脏携带各种让药物迅速分解的酶，使药物很快从身体内排出。亚裔由于其吸收状态较为低下，却需要比白人服用较小剂量之药物，包括控制胆固醇，防止血栓和降低血压等药物。

Ethnicity plays a significant role in the process of drug metabolism. African descendants usually require higher drug doses than Asians or Caucasians because they, as the world’s oldest ancestral group, carry more diverse liver enzymes that allow them to break down drugs and eliminate them more quickly.  Asians, meanwhile, tend to require lower drug doses than do Caucasians to control certain conditions, such as high cholesterol, blood clotting and hypertension, due to their inferior metabolizer status.

在对病人吸收药物能力一无所知情况下盲目开处方会导致不可设想的后果。有一大部分夏威夷居民携带某种基因变种，使他们服用中风后防止血液凝结的药物后出现危及生命的药物中毒。2014年， 夏威夷州向制药商Bristol-Myers Squibb and Sanofi-Aventis发起法律诉讼，指控其大力推广一种令这一太平洋岛屿的居民服用后出现高度死亡率的药物。

Prescribing drugs while ignorant of patients’ metabolizer status could cause deadly consequences. A significant portion of Hawaiian population carry gene variants that could render them dangerous to Plavix, a drug used to prevent blood clots after a stoke. In 2014, the State of Hawaii filed a suit against Bristol-Myers Squibb and Sanofi-Aventis for allegedly marketing a drug that left many Pacific Islanders dying at a higher rate wile taking it. 

但即使那些来自同一族裔社区的人士，其药物反应的基因组合也会出现差异。令人庆幸的是，在不久的将来，一种能分析病患是否能安全服用某种药物的基因测试将正式进入加国药品市场，让医生能预知其病人是否能有效地吸收他所开的处方药，特别是那些患有象我这类忧郁症和焦虑症的病人。有些医生预测安省政府将在两年内为这种测试买单。

But people of the same ethnicity can have very different genetic drug profile. The good news is that a generic test analysing whether a medication is safe and effective for each individual will soon available on the Canadian pharmaceutical market, allowing doctors to predict which drug a patient will adequately metabolize, particularly for patients suffering depression and anxiety like myself. Some doctors believe that Ontario government may cover pharmacogenetic testing within two years.

但目前这一测试仅限于那些包括有钱人士和公司高管等在内的特权阶层。一名了解其药物反应之基因组合的医生在近期的手术中仅仅服用血液稀释剂正常剂量的一半。他表示：“这种测试尚不能适用于加国全民大众，这让我感到非常内疚。”

But the testing is currently only available to the privileged few – such as company executives and the well heeled individuals. A doctor who, knowing his genetic drug profile took half the regular dose of a blood thinner during a recent surgery, said “It makes me feel guilty that this is not universally available.”

这名医生享受的测试让我感到嫉妒。如果我早就了解我的药物基因反应测试结果，我一开始就会服用正常剂量一半的药物，不必走那么多弯路，受那么多罪了。

And it has made me jealous. Had I armed with this powerful genetic test results -- I would have been given the right dose of anti-depression at the outset -- without going through the side effects and the additional stress.