How often should alendronic acid be taken for osteoporosis?

• A. Once daily.
• B. Twice daily.
• C. Once weekly.
• D. Once monthly.

Answer: (C)

Dosing frequency is chosen to balance long-term efficacy with how well patients can stick to a regimen. Alendronic acid has very low oral bioavailability and must be taken with plain water on an empty stomach, with patients staying upright for at least about 30 minutes afterward to reduce irritation to the esophagus. For osteoporosis, similar fracture prevention is achieved with either daily or weekly dosing, but weekly dosing is easier to maintain over the long term. This better adherence translates into comparable real-world outcomes, so the standard approach is to take it once weekly. Monthly dosing is not the usual regimen for this medication. Therefore, the recommended schedule is once weekly.