Bisphosphonate
Also called: bisphosphonates, alendronate, risedronate, zoledronic acid, Fosamax, Actonel, Boniva, Reclast
What it means
Bisphosphonates are osteoporosis medications — like alendronate, risedronate, and zoledronic acid — that slow down the cells which break down bone, helping bone-building catch up.
If you have osteoporosis, understanding how your medication works helps you make sense of why your prescriber recommends it and what questions to ask over time.
Bisphosphonates are a family of osteoporosis medications that includes alendronate, risedronate, and zoledronic acid, sold under brand names like Fosamax, Actonel, Boniva, and Reclast. They work by binding to bone mineral and being taken up by osteoclasts, the cells that break down bone, which impairs those cells' ability to resorb bone tissue. This slows the removal side of bone remodeling, letting bone-building catch up. They belong to a group called antiresorptives, as opposed to anabolic agents that actively build new bone.
These are the most commonly prescribed and most studied osteoporosis drugs, with large randomized trials showing meaningful reductions in vertebral and hip fracture risk for people with osteoporosis. They're also inexpensive and have decades of safety data behind them. The tradeoffs are real but uncommon, including digestive irritation with oral forms, and two rare complications — osteonecrosis of the jaw and atypical femoral fracture — associated mainly with long-duration use.
Because bisphosphonates linger in bone for years, guidelines discuss a 'drug holiday' after roughly 3 to 5 years for many patients. This, along with any decision about starting, continuing, or stopping the medication, is a conversation to have with your prescriber rather than something to decide alone. If you're taking supplements alongside a bisphosphonate, it's worth telling your doctor so your full regimen can be coordinated.
How sure is this?
Graded Strong Clinical Evidence: Supported by multiple well-designed clinical studies in humans. Read each study with its grade in mind. One study is a piece of the picture, not the whole of it.
Where the Academy teaches it
This page is the short version. The lessons teach it in full, with the context around it and a quiz to lock it in.
Questions people ask about this
Bone medications generally work in one of two ways: they either slow down the cells that break down old bone (antiresorptives), or they actively stimulate the cells that build new bone (anabolics). Which family your drug belongs to tells you a lot about what it can realistically do, and that's worth asking your prescriber about directly.
Read the full answer →That's a decision for you and your prescriber, not something OsteoStrong changes. Medication and mechanical loading work on different parts of the same system — your drug manages the chemical signalling of bone remodeling, while loading supplies a mechanical stimulus along with muscle, balance and coordination. They're meant to work alongside each other, not replace one another.
Read the full answer →Stopping Prolia (denosumab) isn't a neutral event. Because it doesn't build up in your bones the way bisphosphonates do, its protective effect wears off once doses stop. This can lead to a rapid rebound in bone turnover and a risk of multiple vertebral fractures, sometimes within months — so this is a decision to make with your prescriber, not on your own.
Read the full answer →Related words
Antiresorptive medications, like bisphosphonates and denosumab, slow down the cells that break down old bone,…
Osteoclasts are the cells that break down old bone tissue, working alongside bone-building osteoblasts to constantly…
Denosumab (Prolia) is a twice-yearly injection that blocks RANKL, a signal osteoclasts need to mature, slowing bone…
Osteonecrosis of the jaw (ONJ) is a rare condition where part of the jawbone loses blood supply and fails to heal,…
An atypical femoral fracture is an uncommon break in the shaft of the thigh bone that looks and behaves differently…
A drug holiday is a temporary, prescriber-guided pause from a bisphosphonate medication after several years of use,…
Education only, not medical advice. Decisions about tests, medications and treatment belong with your own doctor. OsteoStrong does not diagnose, treat or cure any disease.
