Prescription drug misuse/abuse in the elderly.

One quarter of the prescription drugs sold in the United States are used by the elderly, often for problems such as chronic pain, insomnia, and anxiety. The prevalence of abuse may be as high as 11 percent with female gender, social isolation, depression, and history of substance abuse increasing risk. Screening instruments for prescription drug abuse have not been validated in the geriatric population. Benzodiazepines, opiate analgesics, and some skeletal muscle relaxants may result in physical dependence; however, tolerance, withdrawal syndrome, and dose escalation may be less common in the older patient. Lower doses may decrease the risk of abuse and dependence; however, fear of abuse often results in a failure to adequately treat symptoms such as anxiety, pain, and insomnia.