Peter P. Lamy

The Elderly and Drug Interactions

D espite many reviews, 1-5 information on drug interactions in the elderly and their possible clinical sequelae is still very incomplete. It is known, of course, that adverse drug reactions occur more often and are more severe in elderly because of altered drug distribution (loss of weight, change in lean body weight/lipid tissue), metabolism (altered liver function), and excretion (changed renal function), the latter factor being most important.3 An altered homeostatic mechanism accounts for an elderly patients lessened ability to compensate for adverse drug effects. Drug interactions occur most often in long-term care institutions in patients with multiple pathology, receiving multiple drugs. The risk is heightened when drugs are prescribed pro re nata.6 Most are predictable and, therefore, a~oidable ,~ by adjustment of dose or administration times, or by selection of an appropriate alternate drug8 The drugs most often involved are not necessarily new and exotic drugs, but old and well-known chronic care drugs, such as diuretics, warfarin, digoxin, oral hypoglycemics, H2-histamine blockers, and nonsteroidals. One needs to remember that not all drug interactions result in adverse effects. Indeed, some are desirable, such as the interacting effects of drugs needed in the stepcare approach in the management of hypertension. Although there is still controversy on whether or not drug interactions occur more frequently in the elderly, because of the larger number of drugs they take, the need is to define the relative risk to older patients and, more importantly, the extent to which drug interactions are avoidable and how. Even if elderly do

DRUGS AND THE GERIATRIC PATIENT

Reasons for caution in administering drugs to old people are discussed. A survey was made of the records of 33 elderly cardiac patients in a teaching hospital, 30 elderly ambulatory patients in the community, and 30 elderly patients in a geriatric hospital. The findings indicated that prescription practices were somewhat different for the hospital patients than for the community patients, but there did not seem to be any reduction in drug dosage on account of the patients advanced age.

Physicians' Knowledge of Prescribing for the Elderly: A Study of Primary Care Physicians in Pennsylvania

The 143 physicians who returned to Temple University Medical School a questionnaire on knowledge of prescribing for the elderly constituted 25% of a stratified random sample of general practitioners (GPs), family practitioners (FPs), and practitioners in internal medicine (IMs) reimbursed under Medicare in Pennsylvania in 1979. The mean score on the 23‐item drug questionnaire was significantly lower (P < .05) than the score deemed adequate by a panel of six experts in the field.

Over‐the‐counter Medication: The Drug Interactions We Overlook

The effective use of medication involves awareness of both the interpersonal interaction between provider and patient and potential drug–drug interactions. Elderly patients are especially vulnerable to drug–drug interactions because many in this population are very likely to be undergoing treatment for two or more concurrent diseases, probably while self‐medicating with over‐the‐counter (OTC) preparations. Both patient and provider behaviors generate poor patient–provider interactions. The elderly patient is unwilling to ask for help or admit weaknesses that may become restrictive; providers often lack training in the psychosocial and economic aspects of geriatric care. The cost of OTC preparations for people over 65 is about half of what they spend on prescription drugs. The effects of salicylate use (as internal analgesics) and antacid use illustrate potential OTC–prescription drug interactions. Aspirin, used with other drugs, can contribute to accidental hypothermia; idiosyncratic reactions are particularly dangerous in the asthmatic patient. In addition, many OTC products contain aspirin but are not clearly labelled as such. Antacid overuse can be detrimental in itself, and antacids can also affect the absorption and excretion of prescribed drugs when they alter gastric or urinary pH. It is suggested that providers pay more attention to dosage form, as this can influence drug effectiveness, particularly in the elderly. The OTC drugs are therapeutically valuable, but providers must be aware of the potential difficulties when patients use them.

THE GERIATRIC PATIENT: AGE-DEPENDENT PHYSIOLOGIC AND PATHOLOGIC CHANGES

Age‐dependent physiologic and pathologic changes are discussed under the categories of the soft tissues, the cardiovascular, digestive, respiratory, skeletal and nervous systems, the genito‐urinary tract, the senses, speech, hearing, visual function, and the nutritional state.

Therapeutics and an Older Population: A Pharmacist's Perspective

Older people are here to stay. Yet, the plethora of health statistics on the elderly has not yet convinced us. We know that those elderly living in the community receive between 20 and even 40 prescriptions a year, that their non-prescription drug use increases with advancing age, and that they constitute up to 65 per cent of all patients in acute care hospitals. Additionally, older people account for 11 per cent of our current population, and 16 per cent of the voting population. Since they vote much more consistently than younger people, they may actually account for over 20 per cent of those who vote. Clearly, an important constituency has grown up, almost overnight, and we need to recognize that fact. Health and the concept of well-being in old age differ from the perception of these concepts at younger ages. A so-called fit elderly person, living alone, being proud of that fact, and not wishing to change it for anything in the world, may suffer from a number of chronic diseases, such as arthritis, congestive heart failure (CHF), hypertension, and diabetes. It would, therefore, not be unusual for this person to receive a number of drugs which would make it possible for him to pursue the activities of daily living. Drugs are probably the most cost-effective modality of‘ chronic disease management. Yet, even when used “correctly” and according to “recognized standards,” they may pose a serious hazard to the elderly patient. Indeed, many of the drugs used for older patients have very narrow therapeutic indexes. In the elderly, the effects of primary aging (physiologic changes with age) combine with those of secondary aging (cumulative pathophysiologic changes with age) and sociogenic aging (cumulative losses of income, family, friends) to make drug responses more variable and less predictable. The result is an increase in adverse drug reactions and drug interactions, and unpredictability in drug actions.

Preparation of Sterile Parenterals Using a Syringe-Needle Attachment Unit

A syringe-needle attachment unit was evaluated in a test designed to show whether or not it would be possible to attach needles to filled syringes with that unit and maintain sterility of the medication. Of 460 syringes filled and closed in a horizontal laminar flow unit, none was contaminated. Based on the moderate sample, it can be concluded that the unit will indeed permit closure of syringes without introduction of contamination.