Patient errors may result from nonadherence for reasons described below. In addition, they often result from use of nonprescription drugs taken without the knowledge of the physician. As noted in Chapters 63 and 64, many over-the-counter agents and herbal medications contain “hidden ingredients” with potent pharmacologic effects. For example, many antihistamines contained in over-the-counter drugs have significant sedative effects and are inherently more hazardous in patients with impaired cognitive function. Similarly, their antimuscarinic action may precipitate urinary retention in geriatric men or glaucoma in patients with a narrow anterior chamber angle. If the patient is also taking a metabolism inhibitor such as cimetidine, the probability of an adverse reaction is greatly increased. A patient taking an herbal medication containing gingko is more likely to experience bleeding while taking low doses of aspirin.
The quality of life in elderly patients can be greatly improved and life span can be prolonged by the intelligent use of drugs. However, the prescriber must recognize several practical obstacles to compliance.
The expense of drugs can be a major disincentive in patients receiving marginal retirement incomes who are not covered or inadequately covered by health insurance. The prescriber must be aware of the cost of the prescription and of cheaper alternative therapies. For example, the monthly cost of arthritis therapy with newer NSAIDs may exceed $100, whereas that for generic ibuprofen and naproxen, two older but equally effective NSAIDs, about $20.
Nonadherence may result from forgetfulness or confusion, especially if the patient has several prescriptions and different dosing intervals. A survey carried out in 1986 showed that the population over 65 years of age accounted for 32% of drugs prescribed in the USA, although these patients represented only 11–12% of the population at that time. Since the prescriptions are often written by several different practitioners, there is usually no attempt to design “integrated” regimens that use drugs with similar dosing intervals for the several conditions being treated. Patients may forget instructions regarding the need to complete a fixed duration of therapy when a course of anti-infective drug is being given.
The disappearance of symptoms is often regarded as the best reason to halt drug taking, especially if the prescription was expensive.
Nonadherence may also be deliberate. A decision not to take a drug may be based on prior experience with it. There may be excellent reasons for such “intelligent” noncompliance, and the practitioner should try to elicit them. Such efforts may also improve compliance with alternative drug regimens, because enlisting the patient as a participant in therapeutic decisions increases the motivation to succeed.
Some errors in drug taking are caused by physical disabilities. Arthritis, tremor, and visual problems may all contribute. Liquid medications that are to be measured “by the spoonful” are especially inappropriate for patients with any type of tremor or motor disability. Use of a dosing syringe is essential in such cases. Because of decreased production of saliva, older patients often have difficulty swallowing large tablets. “Childproof” containers are often “elder-proof” if the patient has arthritis. Cataracts and macular degeneration occur in a large number of patients over 70. Therefore, labels on prescription bottles should be large enough for the patient with diminished vision to read or should be color-coded if the patient can see but can no longer read. Because of impaired hearing, even carefully delivered instructions regarding drug use may not be understood by the patient; written instructions may be helpful.
Drug therapy has considerable potential for both helpful and harmful effects in the geriatric patient. The balance may be tipped in the right direction by adherence to a few principles: 1.
Take a careful drug history. The disease to be treated may be drug-induced, or drugs being taken may lead to interactions with drugs to be prescribed.
2.
Prescribe only for a specific and rational indication. Do not prescribe omeprazole for “dyspepsia.” Expert guidelines are published regularly by national organizations and websites such as UpToDate.com.
3.