Drug therapy in the elderly
Section snippets
Rates of dissolution and absorption
In order for an orally administered drug to reach the bloodstream and then the target organ, it first needs to dissolve and then be absorbed. If the dissolution process is slow because of reduced saliva, gastric, and intestinal fluids, the rate of absorption decreases (increased Tmax) without affecting the total amount of drug absorbed.3 Drugs that need to be absorbed rapidly by the buccal mucosa, such as glyceryl trinitrate, will be absorbed at a slower rate in the elderly since the amount of
Pharmacodynamic changes in aging
In the elderly, there is a natural and progressive loss of function of body tissues at the cellular level. These pharmacodynamic changes are especially important in the central nervous system. Movement disorders and forgetfulness are often the result of changes in the level of neurotransmitters rather than neuronal loss; moreover, mental confusion could be due to alterations in cerebral blood flow, which also produce autonomic changes that could result in bradycardia, augmented vasoconstriction
Drug-drug interactions
Because older people generally use more drugs there is a greater chance for drug interactions. Skoll et al26 reviewed the prescription of drugs for the elderly in a Saskatchewan Prescription Drug Plan and found that 77.3% of the elderly populace had received at least 1 prescription drug from the Saskatchewan formulary. All subgroups of the elderly (ages 65 to 74, 75 to 84, and 85+) received more prescriptions than their middle-aged counterparts. Such multiplicity could lead to a greater
Conclusion
In the use of drugs in the elderly, it must be remembered that the current armamentarium of drugs available for the treatment of cardiovascular, metabolic, and other disorders is, for the most part, designed for the younger adult. Therefore, appropriate modifications must be made for the elderly patient—modifications that take into account the altered physiology, pharmacokinetics, and pharmacodynamics that accompany aging. Use of medications in the elderly should be kept to a minimum, with
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