You have a headache. Do you reach for Tylenol or Advil? Most people have a preference because they have learned over time that one works better than the other at relieving their pain. This type of variability from person to person is true for nearly every medication, whether it requires a prescription or can be purchased over the counter.
Pharmacists, physicians, and researchers have tried for decades to understand why the same medication, at the same dose, can work well for some people but not for others, why some people need higher or lower doses of the same drug, or why some people have side effects, while others do not.
This kind of personalized treatment is an example of what is called precision medicine.
