According to a significant report, we have the technology to usher in a new era in medicine by accurately matching medications to people's genetic code.
Because of small changes in how our bodies function, some medications are rendered useless or even lethal.
A genetic test, according to the British Pharmacological Society and the Royal College of Physicians, can predict how effectively medications will work in your body.
Next year, the tests may be available on the NHS.
Your genetic code, also known as DNA, is a set of instructions for how your body works. Pharmacogenomics is the science of matching medications to your DNA.
Jane Burns of Liverpool, who lost two-thirds of her skin after a poor reaction to a new epilepsy treatment, could have benefited from it.
When she was 19, she was started on carbamazepine. She got a rash two weeks later, and her parents took her to A&E when she acquired a high temperature and began hallucinating.
The next morning, the skin damage began. "I remember waking up covered in blisters, it was like something out of a horror film, it felt like I'd been on fire," Jane told the BBC.
Stevens-Johnson syndrome, which affects the skin and is considerably more common in persons who are born with particular mutations in their genetic code, was triggered by her epilepsy medication.
Mrs Burns considers herself "very, extremely fortunate" and supports pharmacogenomic testing.
"It's a good thing if it saves your life."
Jane's story may seem unusual, but according to Prof Mark Caulfield, president-elect of the British Pharmacological Society, "99.5% of us have at least one variation in our genome that, if we come across the wrong pharmaceutical, it will either not work or cause injury."
Codeine provides no pain relief to more than five million people in the United Kingdom. Their genetic code lacks the instructions for producing the enzyme that converts codeine to morphine, rendering the medicine useless.
One in every 500 people has a genetic code that puts them at danger of losing their hearing if they take the antibiotic gentamicin.
Some drugs are already based on pharmacogenomics. Previously, 5-7 percent of people would have a poor day.
Scientists studied the top 100 most commonly prescribed medications in the United Kingdom. We already have the technology to roll out genetic testing to guide the use of 40 of them, according to their report.
The genetic study would cost around £100 and could be performed on a blood or saliva sample.
When one of the 40 medications is prescribed, the vision is to complete the test. In the long run, the goal is to test well ahead of time, perhaps at birth if infant genetic testing is approved, or as part of a normal check-up in your 50s.
