Bisphosphonates (Fosamax, Actonel)
Common brand names: Fosamax, Actonel, Boniva, Reclast, Zometa
Three nutrients listed against this medication. The most severe is marked critical.
At a glance
One of the three is marked well documented. The other two carry their own evidence levels.
At a glance
- CalciumCritical · Well documented
- Vitamin D3Critical · Traditionally cited, limited evidence
- MagnesiumModerate · Traditionally cited, limited evidence
Color shows how serious each listed effect is. The label beside it shows how strong the evidence is. The cards below explain each one and show its evidence.
Nutrients it can lower
Mechanism, Bisphosphonates bind calcium in the gut when taken together, preventing both drug and calcium absorption. Must be taken separately.
Common signs, Hypocalcemia, muscle cramps, tetany, paresthesia, cardiac arrhythmia
Chennuru et al. (Intern Med J, 2008; PMID PubMed ID: the permanent number the US National Library of Medicine gives a published paper. Each one links to that paper's record on PubMed. 18284458): symptomatic hypocalcemia was common after zoledronic acid, aggravated by low vitamin D or magnesium.
Calcium 600–800 mg daily, taken at a different time of day from the bisphosphonate, is the practice in common use. Chennuru reports symptomatic hypocalcemia after zoledronic acid aggravated by low vitamin D or magnesium; the timing and the vitamin D3 pairing are not findings of that paper.
Mechanism, Bisphosphonates are clinically ineffective without adequate Vitamin D. D3 is required for calcium deposition in new bone formation.
Common signs, Bisphosphonate treatment failure, persistent bone loss, hypocalcemia, muscle weakness
Adami et al. (Osteoporos Int, 2009; PMID 18551242): vitamin D-insufficient women on anti-resorptive therapy gained three to fivefold less bone mineral density and had 1.5-fold more incident fractures than replete women. Vitamin D must be corrected for bisphosphonates to work: a prerequisite, not a drug-caused depletion.
25(OH)D is tested before starting, because adequate vitamin D status is needed for the drug to work. The cited trial compared vitamin D insufficient women with replete women and set no target concentration; EBL publishes none.
Mechanism, Magnesium binds bisphosphonates in the GI tract, reducing absorption of both. Required for proper osteoblast function and hydroxyapatite crystal formation.
Common signs, Muscle weakness, poor bone quality despite density preservation
Bone remodelling is magnesium-dependent, but there is no evidence bisphosphonates deplete magnesium. Speculative.
Magnesium 300–400 mg daily is a range in common use, not from a trial cited on this row, and it is separated from the bisphosphonate dose because divalent minerals reduce its absorption.
For your next appointment
It prints or saves as a single page. Whether to add a supplement for a nutrient this medication may lower is a decision for your prescriber.
Disclosure
These statements have not been evaluated by the Food and Drug Administration. Any grade on this page describes the strength of published human trial evidence in the populations studied. It is not a recommendation for any individual and is not medical advice. Starting, stopping or changing any supplement or medication is a decision for your physician.
Grades move when new trials publish. A free monthly email lists every grade EBL moved, with the reason and the trial behind it: the sign-up is on the Evidence Log →