To evaluate the safety of cyclic etidronate in routine clinical practi
ce, we obtained information from 550 general practices in the United K
ingdom that provide the medical records to the General Practice Resear
ch Database. A group of 7977 patients taking cyclic etidronate and two
age-, gender-, and practice-matched control groups, one with osteopor
osis and one without, were analyzed. For the group taking cyclic etidr
onate, the average age was 71.6 years and follow-up was 10,328 person-
years. Conditions that do not induce osteoporosis generally occurred i
n these patients at a rate comparable to that in the control groups. T
he incidence of osteomalacia was low and comparable between patients t
aking cyclic etidronate and controls with osteoporosis. No medically s
ignificant increases in frequency were observed among patients taking
cyclic etidronate for a broad group of diseases that may potentially b
e induced by exposure to the drug. These data support the favorable ri
sk:benefit ratio of cyclic etidronate.