Further contributing to this problem is the fact that doctors do not routinely question patients about their use of nonprescription remedies, and patients rarely volunteer this information unless asked directly.

Consumers typically decide what supplements to take based on internet postings or advice from friends. Yet one review of 338 retail websites for the eight most widely used herbal supplements revealed that 80 percent made at least one illegal and unsubstantiated health claim, with more than half suggesting that the substance could treat, prevent or even cure a specific condition.

Even doctors who are well-informed may have difficulty determining the best or safest medications to prescribe for their elderly patients because most of the studies done to gain marketing approval deliberately exclude older people or those with an unrelated chronic health problem.

Thus, prescribing doctors may not know if the drug they order is safe for patients with, say, kidney or liver impairment who may require a lower-than-usual dose or a different drug entirely. A good drug that is not appropriately prescribed could be worse than no drug for patients.

Medical judgment is often required to enhance safety. To foster compliance with prescribed remedies and minimize the risk of side effects for older patients who require multiple medications, doctors may choose to “underprescribe” and prioritize treatments for serious conditions already diagnosed over preventive therapies for conditions with a less immediate impact on patients’ quality of life.

On the other hand, some drugs prescribed years earlier may no longer be necessary and can be safely discontinued. The patient, for example, may now have a short life expectancy that renders pointless a preventive medication taken to lower cholesterol or increase bone density. However, it is important to gradually taper many drugs to avoid dangerous symptoms caused by an abrupt withdrawal.

Affordability is yet another consideration. Even with insurance coverage for prescription drugs, many newer, more effective medications involve co-payments that strain the budgets of the elderly. Patients may decide to skip doses or cut drugs in half to make them go further, and in doing so render them less effective or ineffective.