Alendronate daily, weekly in conventional tablets and weekly in enteric tablets: preliminary study on the effects in bone turnover markers and incidence of side effects.

Bisphosphonates are now in the vanguard of osteoporosis treatment. Frequently, gastro-oesophageal symptoms are associated with these drugs. The objective of this study was to compare side effects and bone turnover markers in postmenopausal women who had received alendronate daily or weekly in tablets with or without enteric coating. We conducted a randomised, double-blind, 3-month trial. The trial involved 75 volunteers, aged 45-58 with moderate to severe osteopenia (T-score lower than -2 SD) assessed by quantitative ultrasound. Women were assigned randomly to receive: (a) alendronate 10mg/day: (b) alendronate 70 mg once a week: or (c) enteric alendronate 70 mg per week. We recorded side effects, C-telopeptide, osteocalcin and urine hydroxyproline at the start of the study and at 3 months. After 3 months, pyrosis (heartburn) was noted by seven women in group A (28%), three in group B (12%) and two in group C (8%); nausea: by one woman in group B; and headache by one patient in each group. C-telopeptide (A: 40.7%; B: 34.1% and C: 38.5%); hydroxyproline (A: 31.1%;B: 25.3% and C: 31.5%) and osteocalcin (A: 27.0%; B: 25.4% and C: 25.1%) decreased similarly in the three groups. Weekly intake of alendronate, whether conventional or enteric-coated; is associated with less heartburn and nausea. Enteric alendronate has a similar action to the conventional tablets on biochemical markers.