Therapeutic Effect - Pharmacology Example

Pharmacology Example

For example, it is widely promoted that "natural" or "organic" agents are more healthy. However, everything in the world has multiple and varying responses when used; both desirable and undesirable effects are inherent parts of the total response. Even water – on which all life on earth depends – can have undesirable, even fatal effects; while increased intake of water can save a dehydrated patient, too much water can lead to water intoxication, which can result in death, such as in severe pulmonary edema.

As a simple example, the therapeutic effect of diphenhydramine, when used for nasal congestion, is to lessen mucous membrane secretions and the side effect is drowsiness. However, when used for insomnia, as in many over-the-counter preparations, the therapeutic effect of diphenhydramine is drowsiness and the side effect is mucous membrane dryness, which is undesirable, especially if the person using the agent for sleep is already suffering from dry membranes. The more important issue is not the agent, but the situation in which the therapeutic agent is used; a change in the situation can easily totally reverse what is usually considered a therapeutic versus an undesirable side effect.

Diphenhydramine was originally marketed under the brand name Benadryl in the early 1950s. When taken orally, it typically induces two behavioral responses: (1) drying of mucous membranes, potentially helpful in cases of increased nasal congestion and (2) drowsiness. Diphenhydramine was promoted for reducing nasal congestion, thus response 1 was the considered the therapeutic effect. Since response 2, the drowsiness response, was typically not viewed as desirable, drowsiness was termed a side effect.

When diphenhydramine is used as a treatment, these two effects, individual responses, are always bound together and cannot be separated. Even though the dose can be changed and the relative degree of the two responses may be reduced or increased and the degree of the two different responses may be somewhat different at different doses, the two responses cannot be separated. For simplicity of illustration, only two typical responses are mentioned. For completeness, be aware that as with most treatments people usually exhibit additional responses to diphenhydramine beyond the two mentioned.