BOSTON, MA-As people grow older, they are likely to be taking several drugs for medical conditions. In view of this, a Harvard Medical School specialist stresses the need for physicians prescribing psychiatric drugs to use lower dosages and to monitor older patients carefully for potential side effects. Carl Salzman, MD, associate professor of psychiatry at Harvard Medical School and director of psychopharmacology at the Massachusetts Mental Health Center explains that the need for such caution is due to the "increased sensitivity of the aging central nervous system to all kinds of drugs."
The major differences between drugs used for anxiety, depression, or other emotional problems of the older patients (defined as 65 and older) are not their effectiveness but the side effects to which these patients have grown sensitive. As an example, the Harvard psychiatrist cites one of the most common side effects of psychotropic drugs - dry mouth. This "anticholinergic" side effect also occurs in younger patients, he points out, yet for older patients this symptom may lead to improperly fitting dentures, the loss of fillings from teeth, and the intake of excess water that may upset kidney function. Older patients often refuse to take medications that produce this symptom, leading to the problem of ineffective therapy brought about by "low compliance."
Among the more serious consequences of the anticholinergic side effects are several conditions that mimic dementia, Dr. Salzman reports. "There may be disorientation, memory loss, agitation, assaultiveness, visual hallucination - all of which are likely to be worse during the evening or at bedtime. This kind of side effect often is misdiagnosed, regarded as dementia, classified as Alzheimer's disease (progessive brain atrophy), may lead to a suspicion of cancer metastasis to the brain, or may be considered just bad old age."
Dr. Salzman also discusses the potential dangers posed by the most commonly used psychiatric drugs, the benzodiazepines, and their potentially adverse impact on older patients. "Used regularly and for long periods of time, these drugs can lead to a patient becoming uninhibited, confused, agitated, forgetful, or oversedated," he explains. "In general, short -acting benzodiazepines are better for older people."
He describes one of the new drugs for depression, trazodone, as "very effective in the elderly with few anticholinergic or cardiovascular side effects. But there is a problem with sedation," he says, adding that "actually, after several weeks of continuing use, this sedating effect will wear off." Older people are much more sensitive to the sedating side effects of all drugs than are younger people.
The Harvard psychiatrist also presents some statistics on the extent of drug taking by older individuals, including a survey conducted by himself and his associates at a Boston general hospital.
An estimated 25% of the elderly depend on prescription drugs in order to continue their daily activities. More than 85% of the elderly ambulatory patients are on a variety of drugs. If they are hospitalized, that number increases to 95%. As for psychiatric drugs, they are perhaps more widely used than realized. More than half of the patients residing in a skilled nursing facility receive psychotropic drugs, but so do almost half of the noninstitutionalized elderly. "Older people are much more likely to take a variety of drugs," Dr. Salzman says. "The number depends on their age and whether they are at home or living in an institution.
"In our own survey at a local hospital, we found that, on the average, older patients were taking eight drugs. One-third of the older patients being treated for a medical condition also receive psychotropic drugs. Among them are neuroleptics, antidepressants, and sedatives. In our survey we found that flurazepam, a benzodiazepine sleep medication, was the most prescribed drug, often in combination with other drugs."