Patient education is, as others on the thread have pointed out, the key. If you're taking medication, you need to familiarize yourself with its side effects, and the drugs that it can react harmfully with. That would be sort of the first line of defense. I've often thought that doctors, when they prescribe these medications, ought to double-check with the patients as to what other drugs they are taking. In this day and age, when there is so much information out there, there really is no reason not to think about it and act responsibly, whether you are a caregiver or a patient.