Timing of cyclical etidronate.

Area of Science:

• Bone Metabolism and Pharmacology
• Geriatric Medicine
• Pharmacokinetics

Background:

• Cyclical etidronate is a bisphosphonate used to treat osteoporosis.
• The timing of etidronate administration may influence its efficacy in improving bone mineral density (BMD).
• Previous guidelines suggest a 2-hour fasting period around etidronate intake.

Purpose of the Study:

• To investigate the impact of etidronate timing on lumbar spine BMD changes.
• To determine if the timing of etidronate administration affects treatment outcomes.

Main Methods:

• A questionnaire was sent to 52 patients on cyclical etidronate for at least 1 year, assessing the time of day etidronate was taken.
• Patients were categorized into three groups: fasting on waking, during the day, or before bed/night.
• Lumbar spine BMD was measured at baseline and after 1 year.

Main Results:

• Patients taking etidronate before bed/night showed the greatest mean BMD increase (5.4% at 1 year, 7.5% over 2.7 years).
• Patients taking etidronate while fasting on waking showed moderate BMD increases (3.1% at 1 year, 5.6% over 2.7 years).
• Patients taking etidronate during the day had minimal BMD changes (-0.14% at 1 year, 1.2% over 2.7 years), significantly less than the other groups (P < 0.05).

Conclusions:

• The standard 2-hour fasting rule may be insufficient when etidronate is taken during the day.
• Taking the etidronate component of cyclical therapy in the early morning or late evening/at night optimizes its effect on lumbar spine BMD.
• Timing is a critical factor for maximizing the therapeutic benefit of cyclical etidronate therapy.