Ab1805

Timing of cyclical etidronate

P.J. Ryan

Osteoporosis Unit, Department of Nuclear Medicine, Medway Hospital, Gillingham, Kent, Uk.

ABSTRACT
Objective
The importance of the timing of the etidronate component of cyclical etidronate was investigated in a study examining changes in lumbar spine BMD.

Methods
Seventy patients who had been taking cyclical etidronate for at least 1 year and who had baseline BMD studies and a further scan 1 year later were mailed a questionnaire asking about the time of day they took the etidronate component. Replies were received from 52 patients who were of average age 67.5 years (SD 6) and had been on therapy for an average of 2.7 years. Patients were divided into 3 groups according to when they took etidronate: Group A - Fasting on waking, Group B - During the day, and Group C - Before retiring to bed or during the night. All patients except 2 claimed to avoid food and drink apart from water for 2 hours either side of taking etidronate.

Results
The mean increases in BMD over 1 year were 3.1% Group A, -0.14% Group B, and 5.4% Group C and the total change over duration of use were 5.6%, 1.2% and 7.5%, respectively. There were significant differences (P < 0.05) between group B and the other 2 groups at 1 year and over 2.7 years.

Conclusion
We conclude that the 2-hour rule may be insufficient for taking etidronate during the day and that the etidronate component of cyclical etidronate is best taken in the early morning or late evening/at night.

Key words
Bisphosphonate, etidronate, osteoporosis, vertebra.

Please address correspondence and reprint requests to: P.J. Ryan, Md, Frcp, Consultant Physician, Osteoporosis Unit, Department of Nuclear Medicine, Medway Hospital, Gillingham, Kent Me7 5ny, Uk.