The older adult often tolerates the presence of two or more chronic disease states, many of which are progressive in nature. As most disease has effects on more than one body system, interdependent physiologic reserves are further compromised. When an acute problem occurs, whether related or not to the chronic diseases, the patient decompensates. The consequence may be as simple as a visit to the doctor's office. However, results often include hospitalization or a decline in function that is not overcome with rehabilitation or long-term nursing care.
Death is the ultimate decompensation.
The issue, for the purposes of this discussion, is understanding that our pharmaceutical manipulations inadvertently may cause devastating consequences to our elderly patients. Homeostatic changes encountered during normal aging may alter sensitivity to a given medication, resulting in pharmacodynamic effects. Such effects may differ markedly from reactions seen in younger patients. Multiple drugs, drug side effects, drug interactions, and drug-disease interactions contribute to the risks assumed when treating the elderly patient. Common pharmacodynamic reactions in older patients include agitation, falls, confusion, constipation, incontinence, memory deficits, dizziness, and depression.