Prescriptions: Complying with the Doctor's Orders
"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.
Effects of Medicines on Disease
For each of these purposes the medicines must be taken according to the doctor's directions in order for the patient to benefit. If the medication is inappropriately taken or discontinued, illnesses can persist unnecessarily, inactive illness can become active again, complications of the illness can develop, or an illness that was being prevented may occur.
Also, if the entire prescribed course of antibiotics is not completed, the bacteria may only be reduced in numbers, not eradicated, and the infection may return in full force after the antibiotics are stopped. Another potentially serious response to an incomplete course of antibiotics is bacterial resistance. Bacterial resistance occurs when a small number of bacteria survive because the course of antibiotics was not completed. The bacteria that survive are likely to be resistant to the antibiotic, that is, they have developed ways to block the effect of the antibiotic. When the antibiotic is next used, for example, to treat the infection when it recurs, the antibiotic is no longer effective. In this situation, the next infection can be more serious and it may be necessary to change to other antibiotics to stop the infection.
Timing of Medications