SAN DIEGO — About half of postmenopausal women who take bisphosphonates for osteoporosis take at least three concomitant medications and 15% take six or more, researchers led by Dr. Sydney Lou Bonnick reported during a poster session at the annual meeting of the International Society for Clinical Densitometry.
“Patients receiving bisphosphonate therapy for postmenopausal osteoporosis have a substantial pill burden,” the researchers wrote in their poster. “Adherence to therapy may be improved if physicians consider prescribing more convenient, less frequently dosed medications.”
Dr. Bonnick, medical director of the Clinical Research Center of North Texas in Denton, and her associates obtained patient prescription information from November 1999 to June 2004 from NDCHealth, a database that contains records from 14,000 retail pharmacies in the United States.
They identified women aged 50 years and older who were receiving alendronate or risedronate, which were the bisphosphonates approved for osteoporosis treatment during the study period.
Concomitant medications were defined as a minimum of a 2-week supply of medications that are prescribed in the same month as are a minimum of a 2-week supply of bisphosphonates.
Between November 1999 and June 2004 the number of women in the database using bisphosphonates rose from 78,909 to 250,286. Of the women prescribed concomitant medications, 74% were on two or more additional medications, 52% were on three or more, and 15% were on six or more.
The percentage of women taking six or more concomitant medications increased from 12% to 19% during the study period.
The most common concomitant drugs taken were cholesterol reducers, synthetic thyroid hormones, calcium channel blockers, β-blockers, ACE inhibitors, and systemic antiarthritis medications.
Dr. Bonnick and her associates observed that by the end of the study, women on daily bisphosphonate therapy were on a higher mean number of concomitant medications, compared with those on weekly bisphosphonate therapy (4.16 vs. 3.77, respectively). In addition, women aged 75 years and older were on a higher mean number of concomitant medications, compared with those aged 50–64 years (3.97 vs. 3.09, respectively).
GlaxoSmithKline supported the study.