Prescriptions: Complying with the Doctor's Orders
Medical Author: William Shiel, MD, FACP, FACR
"Why do I have to follow the directions, doctor? And, why should I stay on my medicine when my symptoms have improved?"
I will review aspects of these issues with the goal of explaining the reasons for the doctor's orders and why it is important to comply with, that is, to follow the directions for taking medicines. I will discuss the following concepts:
Medicines must be administered in such a way that the balance of absorption and metabolism maintains a specific level (concentration) in the blood. For each medicine, scientists have determined the optimal dose and frequency of dosing to maintain concentrations in the blood that are high enough to maximize beneficial effects but low enough to avoid toxic side effects. If the doses are too low or are taken too infrequently, the medicine may not be effective. If the doses are too high or are taken too frequently, toxic side effects may occur.
Medicines must be taken only for the purpose for which they are intended. Doctors refer to these purposes as "indications." A medicine that is taken for an indication other than what the doctor prescribes it for has little chance of providing any benefit but it still can cause harm due to toxic side effects.
There also are reasons that some people should not take some types of medicine, even if the medicine is good for the condition that they have. These reasons are called "contraindications." For example, people who are allergic to some medicines should not take related medicines, and some people may have a second, unrelated illness that some medicines can seriously worsen. For these reasons, and others, people should never take another person's medication without a doctor's specific instructions.