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Alendronate (Fosamax)

Bisphosphonateprescriptionoral · inferred

Nitrogen-containing bisphosphonate for osteoporosis (post-menopausal, male, glucocorticoid-induced) and Paget's disease. Typical dose 70 mg PO weekly (or 10 mg daily) on empty stomach with plain water, upright for 30 minutes. Oral bioavailability extremely low (~0.6%). Circulating drug clears within days but bone-incorporated drug persists for years (bone matrix half-life ~10 years). Effective modeling half-life used here (10 days) represents circulating/active depot component; true bone depot is multi-year.

Projected serum levels — 70 mg, once daily

Alendronate (Fosamax)
Alendronate (Fosamax) modeled serum levels, 70 mg once daily over 15 days Population-based pharmacokinetic estimate. Steady state reached after approximately 1 days. 0 0.25 0.50 0.75 1 Day 0 Day 4 Day 8 Day 11 Day 15 Time on a regular schedule ≈ steady state · day 1

Maintenance schedule: 70 mg once daily (oral).

Modeled steady state after ~1 days: peak ≈ 0.40 mg, trough ≈ 0.082 mg body load. Population-based estimate over 15 days for a 70 mg dose at a 70 kg reference body mass — the interactive app scales curves to your doses, timing, and body mass.

Key facts

Category
Bisphosphonate
Route modeled
Oral
Model confidence
inferred
Half-life
7.9 h
Common dose
70 mg
Suggested maximum
70 mg/day
Reference dose range
10–70 mg (single dose)
Suggested cadence
once daily

Documented interactions

  • caution
    Boron + Alendronate (Fosamax) Chelation

    Alendronate (Fosamax) (bisphosphonate) forms insoluble complexes with Boron in the GI tract, reducing absorption of both.

  • caution
    Calcium (Citrate) + Alendronate (Fosamax) Chelation

    Alendronate (Fosamax) (bisphosphonate) forms insoluble complexes with Calcium (Citrate) in the GI tract, reducing absorption of both.

  • caution
    Calcium (supplement or Ca-rich non-dairy food) + Alendronate (Fosamax) Chelation

    Alendronate (Fosamax) (bisphosphonate) forms insoluble complexes with Calcium (supplement or Ca-rich non-dairy food) in the GI tract, reducing absorption of both.

  • caution
    Chromium (Picolinate) + Alendronate (Fosamax) Chelation

    Alendronate (Fosamax) (bisphosphonate) forms insoluble complexes with Chromium (Picolinate) in the GI tract, reducing absorption of both.

  • caution
    Copper (Bisglycinate) + Alendronate (Fosamax) Chelation

    Alendronate (Fosamax) (bisphosphonate) forms insoluble complexes with Copper (Bisglycinate) in the GI tract, reducing absorption of both.

  • caution
    Iron (Bisglycinate) + Alendronate (Fosamax) Chelation

    Alendronate (Fosamax) (bisphosphonate) forms insoluble complexes with Iron (Bisglycinate) in the GI tract, reducing absorption of both.

Serum checks 11 modeled interaction pairings for alendronate (fosamax) across your whole stack — absorption conflicts, enzyme inhibition, and nutrient depletion included.

Research behind this entry

  1. Pharmacokinetics of alendronate Porras AG et al. · Clinical Pharmacokinetics, 1999 DOI

    Foundational PK review documenting alendronate's very low oral bioavailability, rapid plasma clearance, extensive bone uptake, and multi-year bone half-life.

  2. Randomised trial of effect of alendronate on risk of fracture in women with existing vertebral fractures (FIT) Black DM et al. · Lancet, 1996 DOI

    Fracture Intervention Trial establishing alendronate's efficacy in reducing vertebral and hip fractures in postmenopausal women with prior vertebral fracture.

2 published studies referenced in the app, each with a plain-language summary.