Drug HolidayChanges in Biochemical Markers of Bone Turnover (Serum CTX and PlNP) After Initiation of a "Drug Holiday" From Bisphosphonates

Inclusion Criteria:

1. Postmenopausal women or males >50 years who have taken oral bisphosphonates (risedronate or alendronate) for five years or more, and in whom it is considered reasonable to initiate a holiday from the medication, or those who have been on a holiday for up to 3 months will be eligible for screening visit.
2. Subjects whose 25(0H) D level is above 30 ng/ml (subjects with 25(0H)D from 10-29 ng/ml may be included after supplementation and assessment of serum 25(0H)D) level is above 30 ng/ml.

-

Exclusion Criteria:

1. Current steroid treatment at or greater than 5 mg/day prednisone or equivalent.
2. The use of any other bone active medication other than risedronate or alendronate.
3. The use of teriparatide within the past 4 years.
4. A contra-indication to the discontinuation of bisphosphonate (e.g. fracture during treatment, extremely low t-score).
5. Subjects with fasting serum sCTX less than 100 pg/ml or greater than 300 pg/mL while taking bisphosphonates.
6. Failure to bring 25(0H)D serum level to 30 ng/ml or greater.
7. Metabolic bone disease other than osteoporosis.
8. Abnormal thyroid function (may be included when thyroid function is shown to be normal by TSH). Per local lab assessment.
9. Evidence of failure to adhere to bisphosphonate use -