Seniors are heavy users of medications. Despite strong evidence that some medications are associated with an increased risk of serious adverse consequences in seniors, physicians prescribe, pharmacists dispense, plans pay and seniors suffer. One such adverse consequence is a fall secondary to dizziness or instability of gait. A fall with a resulting fracture is a leading cause of hospitalizations and deaths of seniors. OBJECTIVES: To advance the quality of its prescription drug benefit, a telecommunications company studied whether taking prescription drugs both known or suspected of causing dizziness or instability of gait in seniors increase the likelihood of fractures. The prescription drugs studied included: propoxyphene and combinations; hydantoin anticonvulsants; benzodiazepines; selective serotonin reuptake inhibitors; and tricyclic antidepressants. METHODS: This analysis studied the rate of hip fractures in a group of 35,264 members over a five-year period from 1996 to 2000. Each member in the study reached the age of 65 by January 1, 1996. Parametric duration regression models were used to quantify the impact of taking certain prescription drugs on the likelihood of subsequently having a hip fracture and to control for differences between study members with hip fractures and those without. RESULTS: Nearly 4 percent of the study population experienced a hip fracture during the time period. Each additional year of age increased the likelihood of having a hip fracture by 10.5 percent. Females were 73 percent more likely than males to have a hip fracture. Members who took amitriptyline were 48 percent more likely, and members who took temazepam were 27 percent more likely to have a subsequent hip fracture during the study period. CONCLUSIONS: Amitriptyline and temazepam increased the likelihood of hip fracture among Medicare-eligible plan members. The telecommunications company will use this evidence to reduce the use of these medications, when appropriate, by its members.