March 1st 2004
Numerous factors put elderly patients at risk for adverse drug events. On average, they take at least 6 medications a day, which increases the likelihood of drug-drug interactions. In addition, many drugs that are safe and effective in younger patients are inappropriate for older persons because of age-related changes and comorbid conditions that affect absorption, distribution, metabolism, and elimination. First-pass metabolism decreases with age, which may increase systemic absorption of some oral nitrates, ß-blockers, estrogens, and calcium channel blockers. The age-related rise in body fat increases the volume of distribution of lipid-soluble compounds, such as diazepam, and prolongs clearance. About two thirds of elderly persons have impaired kidney function; in these patients, the dosage of renally excreted drugs-such as digoxin-needs to be reduced. Other strategies for avoiding adverse drug events are detailed here.