Bisphosphonates: Slowing the breakdown of bone.
I get asked about medications for osteoporosis regularly. While I am a Physical Therapist, not a pharmacist, I do try to keep up with the most common medications my clients are asking about. Bisphosphonates are worth discussing, as they are the most widely prescribed and well-studied medication groups for osteoporosis and osteopenia. If you’ve ever wondered where they came from and how they work, read on.
The history:
1970s: Bisphosphonates were discovered to affect osteoclasts, the cells responsible for bone breakdown
1990s: Bisphosphonates became widely used after clinical studies showed they slowed bone loss by decreasing osteoclast activity.
1990s–2000s: Large clinical trials demonstrated that bisphosphonates significantly reduced fracture risk — especially in the spine and hip — making them the first-line osteoporosis medication.
Today: They remain a first-line treatment for many women with osteoporosis, especially after a DEXA scan shows low bone density or an elevated fracture risk.
The Bisphosphonates Being Prescribed Now
There are several bisphosphonates prescribed today, which fall into two categories: oral medications (taken by mouth) and IV medications (given as an infusion). They all work similarly — by slowing bone breakdown (decreasing osteoclast activity)— but they differ in how often they’re taken and what specific bones they protect the most.
Let’s go over them.
Oral Bisphosphonates
(Taken by mouth, usually first thing in the morning on an empty stomach, and then stay upright for 30-60 minutes.)
1. Alendronate
Brand name: Fosamax
How it’s taken: Pill, once weekly
What it protects: Spine + hip
Why it’s used: The most prescribed bisphosphonate; strong evidence for fracture prevention.
2. Risedronate
Brand names: Actonel, Atelvia
How it’s taken: Weekly or monthly pill
What it protects: Spine + hip
Why it’s used: Atelvia can be taken with food, which may help those with stomach issues.
3. Ibandronate (oral – generic)
How it’s taken: Pill, once monthly
What it protects: Strongest evidence for the spine
Why it’s used: A good option for people who prefer monthly dosing and primarily need spine protection
Note: The brand name Boniva is no longer available
IV (Intravenous) Bisphosphonates
(Given in an infusion center.)
4. Zoledronic Acid
Brand name: Reclast
How it’s taken: IV infusion once a year (about 1/3 to 1/2 of women experience short-term flu-like or achy symptoms after the first infusion.)
What it protects: Spine + hip
Why it’s used: Helpful for those who can’t tolerate oral medications or prefer a once-a-year option.
5. Ibandronate (IV – generic)
How it’s taken: IV infusion every 3 months
What it protects: Strongest evidence for the spine
Why it’s used: An alternative for those needing IV administration but not annual dosing
Note: The oral and IV generic forms are available, this was previously known as Boniva
How Long Do I Need to Take It?
Oral Bisphosphonates (Alendronate, Risedronate, Ibandronate)
Typically taken for 3–5 years, and then reassessed.
After that:
Drug holiday: If fracture risk is low to moderate.
Continue therapy: If fracture risk remains high (low T-scores, fractures, long-term steroids).
Infusion (IV) Bisphosphonates
Reclast (Zoledronic acid) is usually prescribed for 3 years; IV ibandronate for 3–5 years, then reassessed.
How Long Do Bisphosphonates Stay in My Body?
Bisphosphonates bind tightly to bone and remain there for years, even after you stop taking them. This slow release is why:
They keep working after you stop taking them
Drug holidays (time where you come off of them) are possible
There is no “rebound bone loss” when stopping (unlike Prolia - we will go over that in another post)
Each medication is slightly different, but the effects and benefits can last many years; some last as long as 8-10 years.
When Are Bisphosphonates Prescribed?
Bisphosphonates are often prescribed:
After anabolic medications (Evenity, Forteo, Tymlos) to help maintain the bone gained while on those medications
After stopping Prolia, to prevent rapid bone loss and vertebral fractures
When fracture risk is high, if your T-scores are ≤ –2.5, with a fragility fracture, or high FRAX scores
After a drug holiday, if your bone density declines, you may go back on them
After a fragility fracture, including your wrist, spine, or hip
During medical treatments known to weaken bone, including steroids, and certain cancer treatments, such as aromatase inhibitors for breast cancer, which can speed up bone loss and raise your fracture risk
In my experience, when someone gets a recommendation to go on one of these medications for osteoporosis or osteopenia, it can seem scary and intimidating. There is so much to know, and there is a lot of negativity about them on social media. Bisphosphonates have been studied longer and more thoroughly than nearly any other osteoporosis drug, and they are a reliable option for many women who have done all they are supposed to do but are still losing bone. Remember, the women who are doing well with them are not on the internet exclaiming how good they are doing, they are out living their active lives.
Whether you’re considering going on one of these medications for the first time or need to transition to a bisphosphonate after another treatment, knowledge is power. Use this information to have a confident, informed conversation with whoever is recommending you go on one of these drugs.
How do you know if you are doing all you can before going on a drug?
Are you lifting progressively heavier weights on a regular basis?
Have you had your Vitamin D levels checked?
Are you eating sufficient protein to build muscle?
Are you eating whole foods that provide calcium?
Are you addressing whatever factor caused you to lose bone in the first place (corticosteroids, thyroid issues, smoking, etc.)?
Are you doing balance and flexibility work?
Are you getting enough sleep and reducing stress?
As a Physical Therapist, I want you to know that your exercise routine, including progressively heavier lifting, as well as excellent nutrition, is essential for stimulating bone growth.
Join my next Strong Women, Strong Bones Jumpstart to gain a solid base and get started.
Andrea Trombley PT
References
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