This study is designed to determine if combining parathyroid (PTH 1-34) with fluoride (MFPSR) therapy in a cyclic treatment regimen will: (1) produce a greater increase in bone density of the spine than would be produced by either treatment alone; (2) prevent the resistance (i.e., decreased bone formation and no further increase in bone density) that is observed within 18-24 months of PTH therapy; (3) eliminate the calcium deficiency and osteomalacia that can occur with fluoride; (4) prevent excessive bone fluoride content; and (5) result in an increase in bone density which is maintained after treatment is discontinued.

This is a 3-yr, single center, open label, active controlled, randomized study of approximately 99 postmenopausal females with osteoporosis of spine or femoral neck. Patients will be assigned to 1 of 3 groups: 1) PTH 1-34; 2) Fluoride; 3) PTH and fluoride. The treatment period is 3 years with 3-month cycles of therapy. PTH will be administered subcutaneously by injection 600 units daily for 28 days the first month of each 3-month cycle. Fluoride will be administered orally one 76mg tablet twice daily (providing 20 mg fluoride/day), during the last 2 months of each cycle. Calcium will be provided 800mg/day during month 1 and 1500-2000mg for months 2 and 3 of each cycle.

• Drug: PTH 1-34
• Drug: MFPSR-fluoride

• Female, aged 60-80,
• Postmenopausal greater than or equal to 5 years,
• BMD -2.5 to -4.0 at lumbar spine or femoral neck and one standard deviation below young adult mean in the other site, or -2.0 with fracture.
• Vertebral fracture 0-1.

Exclusion Criteria:

• More than 1 vertebral fracture in lumbar spine or more than 4 fracture in the T-L spine.
• Weight less than 45 kg or more than 80 kg, or more than 25% above ideal body weight.
• Present cardiac disease present.
• Diseases or conditions known to affect bone metabolism.
• Therapies with drugs that affect bone metabolism within 6 months.
• Fluoride or Biophosphonates at any time.