1.11 Evaluating Effects

Evaluating the Effects

The nurse is responsible for assessing the client, monitoring lab values, and recognizing side effects and/or adverse effects of medications. Drug dosages should be verified to ensure all are within recommended safe ranges according to the client’s current status, as well as for their potency.

Potency refers to the amount of the drug required to produce the desired effect. A drug that is highly potent may require only a minimal dose to produce a desired therapeutic effect, whereas a drug that has low potency may need to be given at much higher concentrations to produce the same effect. Consider the example of opioid versus nonopioid medications for pain control. Opioid medications often have a much higher potency in smaller doses to produce pain relief; therefore, the overall dose required to produce a therapeutic effect may be much less than that for other analgesics.

The nurse preparing to administer medications must also be cognizant of drug selectivity and monitor for potential side effects and adverse effects. Selectivity refers to the separation between the desired and undesired effects of a drug. Drugs that are selective will search out target sites to create a specific drug action, whereas nonselective drugs may impact many other types of cells and tissues, thus increasing the risk for unintended side effects and/or adverse effects. For example, in Chapter 4 selective and nonselective beta-blockers will be discussed. Selective beta-1 blockers search out specific receptors on the heart to create their effect, whereas nonselective beta-blockers may affect receptors in the lungs in addition to those in the heart, causing potential respiratory side effects like a cough.

A side effect occurs when the drug produces effects other than the intended effect. A side effect, although often unintended, is generally anticipated by the provider and is a known potential consequence of the medication therapy. Examples of common side effects are nausea, vomiting, diarrhea, and drowsiness. In some situations, however, side effects may have a beneficial impact. For example, a side effect of hydrocodone is drowsiness. A client who is having difficulty sleeping due to pain and takes hydrocodone at bedtime may find the drowsiness beneficial in helping them fall asleep.

Conversely, unanticipated effects can occur from medications that are harmful to the client. These harmful occurrences are known as adverse effects. Adverse effects are relatively unpredictable, severe, and are reason to discontinue the medication.^[1] For example, an adverse effect of ciprofloxacin is tendon rupture. Adverse effects should be reported to the pharmacy and tracked as a client safety concern according to agency policy.