Alendronic acid × Iron oral (salts: sulfate, bisglycinate, fumarate, gluconate, polymaltose; heme iron polypeptide, lactoferrin)
ModerateNitrogen-containing bisphosphonate×Oral iron preparations; antianaemic agents
Updated · Methodology
Mechanism
Iron falls into the category of other oral medicines the label requires to be separated from alendronic acid. On top of that, iron's ideal schedule (fasting) collides head-on with the bisphosphonate, which occupies the same slot.
Symptoms
Ferritin that does not recover and flat densitometry: both treatments run at half strength because they compete for the same time slot.
Management
Alendronate keeps the fasting slot and iron moves to mid-morning or evening, with vitamin C and away from dairy. With weekly alendronate the conflict is solved by fixing one day for the bisphosphonate and shifting iron only on that morning.
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Sources
- AEMPS: Ficha técnica Ácido alendrónico semanal Cinfamed 70 mg comprimidos EFG (2024)– AEMPS, CIMA, nº registro 70911, sección 4.5
- NIH Office of Dietary Supplements: Iron – Health Professional Fact Sheet (2025)– NIH ODS, Iron, Interactions with Medications