YOU have a headache and you buy an over-the-counter “extra strength” painkiller. Among other ingredients, it may contain codeine, a well-known drug for pain relief, but one without analgesic properties itself. Codeine is a pro-drug: only after the body transforms codeine into morphine is there any pain relief. But nearly 1 out of every 10 people of European ancestry do not produce the right enzyme to turn codeine into morphine. For them, codeine has no effect. You might like to know if you are one those people.
Other examples of inappropriate treatments are less benign. Take the case of children…
