Recent evidence indicates that many patients with atrial fibrillation—a very common arrhythmia in the elderly—do as well with simple control of ventricular rate as with conversion to normal sinus rhythm. Measures (such as anticoagulant drugs) must be taken to reduce the risk of thromboembolism in chronic atrial fibrillation.
Several age-related changes contribute to the high incidence of infections in geriatric patients. A reduction in host defenses in the elderly is manifested in the increase in both serious infections and cancer. This may reflect an alteration in T-lymphocyte function. In the lungs, a major age and tobacco-dependent decrease in mucociliary clearance significantly increases susceptibility to infection. In the urinary tract, the incidence of serious infection is greatly increased by urinary retention and catheterization in men. Preventive immunizations should be maintained: influenza vaccine should be given annually, tetanus toxoid every 10 years, and pneumococcal and zoster vaccines once.
Since 1940, the antimicrobial drugs have contributed more to the prolongation of life than any other drug group because they can compensate to some extent for this deterioration in natural defenses. The basic principles of therapy of the elderly with these agents are no different from those applicable in younger patients and have been presented in Chapter 51. The major pharmacokinetic changes relate to decreased renal function; because most of the β-lactam, aminoglycoside, and fluoroquinolone antibiotics are excreted by this route, important changes in half-life may be expected. This is particularly important in the case of the aminoglycosides, because they cause concentrationand time-dependent toxicity in the kidney and in other organs. The half-lives of gentamicin, kanamycin, and netilmicin are more than doubled. The increase may be less marked for tobramycin.
Osteoarthritis is a very common disease of the elderly. Rheumatoid arthritis is less exclusively a geriatric problem, but the same drug therapy is usually applicable to both types of disease. The basic principles laid down in Chapter 36 and the properties of the anti-inflammatory drugs described there apply fully here.
The nonsteroidal anti-inflammatory agents (NSAIDs) must be used with special care in geriatric patients because they cause toxicities to which the elderly are very susceptible. In the case of aspirin, the most important of these is gastrointestinal irritation and bleeding. In the case of the newer NSAIDs, the most important is renal damage, which may be irreversible. Because they are cleared primarily by the kidneys, these drugs accumulate more rapidly in the geriatric patient and especially in the patient whose renal function is already compromised beyond the average range for his or her age. A vicious circle is easily set up in which cumulation of the NSAID causes more renal damage, which causes more cumulation. There is no evidence that the cyclooxygenase (COX)-2 selective NSAIDs are safer with regard to renal function. Elderly patients receiving high doses of any NSAID should be carefully monitored for changes in renal function.
Corticosteroids are extremely useful in elderly patients who cannot tolerate full doses of NSAIDs. However, they consistently cause a doseand duration-related increase in osteoporosis, an especially hazardous toxic effect in the elderly. It is not certain whether this drug-induced effect can be reduced by increased calcium and vitamin D intake, but it would be prudent to consider these agents (and bisphosphonates if osteoporosis is already present, see Qaseem reference) and to encourage frequent exercise in any patient taking corticosteroids.
Glaucoma is more common in the elderly, but its treatment does not differ from that of glaucoma of earlier onset. Management of glaucoma is discussed in Chapter 10.