Bisphosphonates — patient guide

This page covers the bisphosphonate family of bone-protective medicines. If your tablet or infusion is alendronate (Fosamax), risedronate (Actonel), zoledronic acid (Aclasta or Zometa), or ibandronate (Bonviva), this is your page.

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Find your medicine

Generic name	Common brand names	Strengths	How often
Alendronate	Fosamax, Alendro, generics	70 mg (most common)	Once weekly
Alendronate + vitamin D	Fosamax Plus, Fosamax Plus D	70 mg + 2800 IU or 70 mg + 5600 IU	Once weekly
Risedronate	Actonel, Risedro, generics	35 mg / 150 mg	Weekly (35 mg) or monthly (150 mg)
Risedronate combo pack	Actonel Combi, Actonel Combi D	35 mg tablet + daily calcium/vit D sachet	Weekly tablet + daily sachet
Zoledronic acid	Aclasta (osteoporosis), Zometa (oncology)	5 mg IV / 4 mg IV	Yearly (Aclasta) or monthly (Zometa)
Ibandronate	Bonviva, Boniva	150 mg oral / 3 mg IV	Monthly (oral) or 3-monthly (IV)

Specialist-only: pamidronate (Aredia) is an older IV bisphosphonate now used mainly in specialist settings — Paget disease where Aclasta isn’t tolerated, some oncology protocols, paediatric metabolic bone disease. Not a general-practice starter.

Closely related — denosumab (Prolia). Different drug class with a similar bone-resorption blocking action. Six-monthly injection. Not interchangeable with a bisphosphonate, and switching between the two is a coordinated specialist decision because of a rebound bone-loss effect when denosumab is stopped without a follow-on agent.

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What it treats

Bisphosphonates are prescribed in several distinct situations. Your reason may be one or more of:

• Postmenopausal osteoporosis — the most common reason. A DEXA T-score at or below -2.5, or a previous fragility fracture, is the usual trigger.
• Male osteoporosis — same threshold logic, fewer years of trial data than in postmenopausal women.
• Glucocorticoid-induced osteoporosis — long-term oral steroid use (prednisolone, dexamethasone) accelerates bone loss. The bisphosphonate is protective.
• Paget disease of bone — a specific bone-remodelling disorder.
• Hypercalcaemia of malignancy and bone metastases — higher doses in oncology, given under specialist care.

The mechanism is the same across all of these — slow the cells that break bone down. The dose, route, and duration differ by indication.

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The basics

1. For oral forms, the dosing ritual matters more than almost anything else on this page. Empty stomach, full glass of plain water, upright at least 30 minutes, nothing else by mouth in that window. See the next section.
2. See your dentist BEFORE starting if at all possible. Tell every dentist you see — forever — that you are on or have ever been on a bisphosphonate.
3. New persistent thigh, groin, or hip pain on therapy is a stress-fracture warning until imaged. Tell us.
4. Don’t stop on your own. If something isn’t working, message us — there are several within-class and out-of-class alternatives.

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The oral dosing ritual — read this twice

This is the single most important behavioural instruction on the page. Following it prevents oesophageal irritation and ensures the medicine is absorbed.

On the morning of your weekly (or monthly) tablet:

1. First thing on getting out of bed, before anything else by mouth — no coffee, no breakfast, no other tablets.
2. Swallow the tablet whole with a full glass of plain tap water (not mineral water — the minerals block absorption, and not coffee or juice).
3. Stay upright for at least 30 minutes — sitting at a desk, standing, walking. Not lying back down. Not bending forward into a slump.
4. Nothing else by mouth for 30 minutes — no food, no coffee, no calcium, no other medicines, no supplements.
5. After the 30 minutes, normal breakfast, normal coffee, normal life.

If the ritual doesn’t fit your life — early-morning rush, swallowing problems, reflux, can’t stay upright reliably — the once-yearly Aclasta infusion skips all of this. Worth asking about.

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What to expect

Oral tablets (alendronate, risedronate, ibandronate oral)

• Most people feel nothing different day-to-day. The medicine is working on bone over months and years; you don’t feel it.
• Mild upper-GI discomfort, reflux, or nausea in the first few weeks is the most common early issue and usually responds to checking the dosing ritual is being followed precisely. New chest pain on swallowing, painful swallowing, or food sticking is different — stop the tablet and contact us.
• A bone-density (DEXA) scan at baseline and again at around 2 years is standard. Some clinicians use bone-turnover blood markers in between.

Intravenous zoledronic acid (Aclasta)

• The infusion itself takes around 15-30 minutes.
• First infusion: around 20-30% of people get a flu-like reaction in the first 1-3 days — fever, chills, muscle and joint aches, headache. Paracetamol cover (1 g four-times-daily for 2-3 days) and pre-loading with fluid the day before reduce the severity. This is not an allergy and gets milder or disappears with subsequent yearly infusions.
• Tingling around the mouth, in the hands or feet, or muscle cramps in the days after is low calcium until proven otherwise — needs a phone call.
• New red painful eye, light sensitivity or blurred vision after an infusion is rare but possible (uveitis / iritis) and needs same-day ophthalmology review.

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Tap any section below to expand the detail.

How does it work?

Bone is constantly being remodelled — the cells that build bone (osteoblasts) and the cells that break it down (osteoclasts) normally work in balance. After menopause, with long-term steroids, in some other states, the breakdown side runs ahead of the building side, and bone density falls.

Bisphosphonates bind to the bone surface and, when an osteoclast tries to digest that piece of bone, the bisphosphonate gets taken up by the osteoclast and switches it off. The breakdown rate drops, bone density holds or improves, and the chance of fracture goes down. The drug stays bound to the bone for years after you stop — which is the basis for the treatment-holiday concept further down the page.

This is structural protection, not pain relief. You won’t feel the medicine working. The way we know it’s working is the DEXA scan, the absence of fragility fracture, and sometimes blood markers of bone turnover.

Side effects in detail

Common (oral forms)

• Upper-GI irritation — reflux, nausea, mild upper abdominal discomfort. Usually responds to checking the dosing ritual is being followed exactly.
• Musculoskeletal aches in the first weeks, usually settling.

Common (IV form)

• Acute-phase reaction — flu-like symptoms (fever, chills, muscle and joint aches, headache) day 1-3 after the first infusion. Around 20-30%. Usually much milder or absent with subsequent yearly infusions. Paracetamol cover and pre-infusion hydration reduce severity. Not an allergy.

Uncommon

• Low calcium after an infusion — especially if vitamin D was not adequate beforehand. Tingling around the mouth, fingers or toes, or muscle cramps. Phone us promptly.
• Eye inflammation (uveitis, iritis) — rare, more common after a first IV dose. New red painful eye, light sensitivity, or blurred vision after an infusion needs same-day ophthalmology review.
• Kidney function change after an IV infusion — particularly if dehydrated or with existing kidney impairment. We check kidney function before each infusion and pre-load with fluid.
• Atrial fibrillation — a signal was raised in the HORIZON trial via the 2007 NEJM HORIZON-PFT report. The size of the signal is debated and not consistently confirmed in later data. Worth knowing, not a contraindication.

Rare but action-driven

• Osteonecrosis of the jaw (ONJ). Around 1 in 1000 to 1 in 10,000 patient-years on oral osteoporosis doses; around 1-2% on the higher monthly oncology doses. Risk goes up with dental extractions, poor oral hygiene, smoking, steroid co-therapy. Symptoms — non-healing tooth socket, exposed bone in the mouth, jaw pain or numbness — need urgent dental and medical review. The international consensus is summarised in the Khan et al. 2015 J Bone Miner Res paper.
• Atypical femoral fracture (AFF). Rare (~3-5 per 100,000 patient-years on therapy) and slightly more frequent beyond about 5 years of use. New persistent thigh, groin, or hip pain — one or both sides — that develops gradually and doesn’t settle is a stress-fracture warning until imaged. X-ray and often MRI of both femurs. The ASBMR task force second report is the reference: Shane et al. 2014 J Bone Miner Res.
• Severe oesophageal irritation / ulceration with oral forms — the dosing ritual is what prevents it. New chest pain, retrosternal burning, painful swallowing, or food sticking means stop the tablet and seek urgent review.

Drugs, food, and alcohol

Tell us or your pharmacist before combining oral bisphosphonate with:

• Calcium supplements, antacids (Mylanta, Gaviscon, Quick-Eze), iron supplements — all block absorption if taken at the same time. Separate by at least 2 hours from the bisphosphonate dose. The cleanest approach is the morning bisphosphonate with plain water, then everything else after the 30-minute window.
• Proton-pump inhibitors (omeprazole, esomeprazole, pantoprazole, rabeprazole, lansoprazole) — may modestly reduce oral bisphosphonate absorption, and there’s a longer-term bone-density signal with chronic PPI use independent of bisphosphonate therapy. Worth periodically reviewing whether the PPI is still needed.
• Anti-inflammatories (ibuprofen/Nurofen, diclofenac/Voltaren, naproxen, celecoxib) — additive GI irritation with oral bisphosphonates. A single Nurofen for a headache is fine. Regular daily use is a conversation. Paracetamol is the safer default.
• Loop diuretics (frusemide) and thiazide diuretics — affect how the kidney handles calcium. Loops increase urinary calcium loss; thiazides reduce it. Worth knowing rather than a hard interaction.
• Glucocorticoids (prednisolone, dexamethasone) — accelerate bone loss and amplify ONJ risk. Often the reason the bisphosphonate was started in the first place; the medicine is protective, ONJ vigilance is heightened.
• Denosumab (Prolia) — do not combine. Switching between bisphosphonate and denosumab is a specialist-coordinated decision because of the rebound bone-loss / fracture risk that follows denosumab discontinuation; a bisphosphonate is often used to consolidate after stopping denosumab.

Food. For the oral forms, nothing by mouth for 30 minutes after the dose, then a normal diet — dairy, fortified plant milks, sardines or salmon with bones, leafy greens, tofu for calcium; protein at every meal for bone matrix.

Alcohol. Light to moderate use isn’t a hard problem. Heavy alcohol use accelerates bone loss independently of the medicine and is worth addressing.

Generic substitution. Generic alendronate, risedronate, zoledronic acid and ibandronate are bioequivalent to the branded versions. If the pharmacist offers a cheaper generic, that’s fine. The dose stays the same.

Monitoring — what blood tests and when

• Before starting: vitamin D level (target 25-hydroxyvitamin D 75-100 nmol/L), calcium, kidney function (eGFR), and a DEXA scan if not already done.
• Before each IV infusion: kidney function and calcium. Vitamin D adequate beforehand.
• After starting (oral): vitamin D and calcium at around 6-12 months; sooner if there have been issues.
• DEXA: baseline and around 2 years after starting, then individualised based on trend and risk.
• Dental review: before starting if at all possible; routine cleans every 6 months; tell every dentist about the bisphosphonate history.
• Message us if you start a new medicine (including over-the-counter or supplements), have an unexplained tooth-extraction socket that won’t heal, develop new persistent thigh / groin / hip pain, or have any unexplained mouth pain, swelling, or exposed bone.

Stopping, pausing, and the treatment-holiday concept

Bisphosphonates are not lifelong by default. They are also not a course-and-done.

The 5-year (oral) or 3-year (IV) reassessment. After about 5 years on an oral bisphosphonate or 3 years on Aclasta, we sit down and look at the picture together — current DEXA, any new fractures, ongoing risk factors (steroids, falls, frailty), and your preferences.

• Continue is reasonable if fracture risk remains high — recent fragility fracture, ongoing oral glucocorticoids, T-score still at or below -2.5, high FRAX score, multiple falls.
• Hold for 1-3 years (a “treatment holiday”) is reasonable in lower-moderate-risk people. The drug retention in bone matrix means the anti-resorptive effect tapers gradually, not abruptly. Re-DEXA and re-assessment time any restart.
• Switch class (for example, to denosumab, teriparatide, or romosozumab) is sometimes the answer — particularly if there’s been an interval fracture on therapy.

Exact thresholds for continuing vs holding vary between guidelines (RACGP, Healthy Bones Australia, NICE, NOF). The wording is deliberately a conversation, not a fixed rule.

Don’t stop on your own. If side effects are the problem, we usually switch rather than abandon. If the dosing ritual is the obstacle, the once-yearly infusion is the answer.

Pregnancy and breastfeeding

Bisphosphonates are retained in bone for years after you stop them. This is the class-distinguishing feature for pregnancy planning.

• Already pregnant: stop the medicine and contact us promptly. Bisphosphonates are not used in pregnancy.
• Breastfeeding: generally avoided.
• Planning future pregnancy (any timeframe): this is a conversation BEFORE starting a bisphosphonate, not after. Long-bone retention means the medicine continues to release for years post-cessation. There are alternative bone-protective approaches without this long-retention issue — worth weighing if pregnancy might be on the horizon at any point.

For the majority audience here — postmenopausal women — this section is informational. Worth knowing the principle for any daughters or younger relatives in whom the question may come up.

Dental care — the standing rule

The single most actionable thing you can do to minimise jaw-related risk on a bisphosphonate:

• Before starting: book a dental review. Complete any planned extractions, implants, or major work first if possible, and allow healing (usually a few weeks to a few months).
• During therapy: routine cleans every 6 months. Meticulous home oral hygiene. Address any new dental issues promptly rather than waiting.
• Forever after: every dentist you ever see needs to know you are on, or have ever been on, a bisphosphonate. This affects how they plan extractions and implants.
• Symptoms to flag urgently: non-healing tooth socket (a tooth extraction site that hasn’t healed at 6-8 weeks), exposed bone visible in the mouth, jaw pain or numbness, loose teeth without an obvious cause.

The risk is real but rare. The protective behaviour is dental coordination, not therapy refusal.

If you’re on a combination tablet or pack

• Fosamax Plus / Fosamax Plus D — weekly alendronate combined with cholecalciferol (vitamin D) in the one tablet, available in two strengths. The dosing ritual is the same as plain alendronate. The combined vitamin D contributes to weekly adequacy; you may still need daily dietary calcium.
• Actonel Combi / Actonel Combi D — a pack with one weekly risedronate tablet plus six daily calcium-and-cholecalciferol sachets. The bisphosphonate ritual applies to the tablet day only. The sachets are a different schedule (daily, with food or as directed on the pack). Read the pack carefully — two components, two different days-of-the-week patterns.

Everything else on this page applies to the bisphosphonate component of either product.

Cost

Most bisphosphonates are PBS-listed under Streamlined Authority for osteoporosis (DEXA T-score at or below -2.5, OR documented minimal-trauma fracture). From 1 January 2026, the PBS co-payment is:

• General patient: up to $25.00 per script
• Concession card holder: up to $7.70 per script

Generic alendronate, risedronate, zoledronic acid and ibandronate cost the same as branded versions at PBS pricing and work the same. Some bisphosphonates fall under the co-payment ceiling — your pharmacist can show you the actual price. The yearly Aclasta infusion is given in a hospital, day-surgery, or infusion clinic — the medicine itself is PBS-listed for osteoporosis; the infusion service may have a separate facility fee depending on the setting. Ask the clinic upfront.

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The integrative view

Most of the patients I see want to do everything they reasonably can in addition to taking the medicine. This section is the longer version of that conversation. Bone is a living tissue — the medicine slows breakdown, your terrain decides whether it can rebuild.

Two principles. First: bisphosphonates work for fracture prevention in the people they’re indicated for, and the evidence (FIT, VERT, HORIZON) is solid. Lifestyle work also moves bone density and fracture risk. The two are not alternatives. Second: the bisphosphonate addresses the bone-cell biology, but most fragility fractures begin with a fall. The package matters more than any single piece of it.

Vitamin D — the input that determines whether the infusion goes smoothly

Vitamin D adequacy is not optional on this medicine — it’s the input that prevents low calcium after a zoledronic acid infusion and supports the bone-building side of the remodelling cycle.

• Target serum 25-hydroxyvitamin D 75-100 nmol/L before starting and throughout therapy.
• Maintenance dose is typically 1000-2000 IU per day (25-50 micrograms). Higher loading doses are sometimes used if you’re deficient at baseline.
• Check the level before starting, again at around 6-12 months, then yearly — or more often if you live above the 35th parallel, work indoors year-round, cover for cultural or sun-safety reasons, or have a malabsorption condition.

Calcium — food first, supplement only if short

• Target total intake (food plus supplement combined) around 1000-1200 mg/day for postmenopausal women and men over 70.
• Food-first sources: dairy (a cup of milk is ~300 mg; yoghurt is similar); fortified plant milks (check the label — usually 240-300 mg per cup); sardines or salmon with bones (~300 mg per small tin); calcium-set tofu (~300 mg per 100 g); leafy greens (kale, bok choy — ~100 mg per cup cooked).
• Supplement only if food intake reliably falls short. 500-600 mg of supplemental calcium with food covers most gaps; doses above 1000 mg/day from supplements have been associated with a cardiovascular signal in some analyses and aren’t usually needed.
• Separate calcium supplements from your oral bisphosphonate dose by at least 2 hours. Same-time calcium blocks absorption of the bisphosphonate.

Protein — the load-bearing nutrient for bone matrix

• Around 1.0-1.2 g/kg/day for older adults on bone-protective therapy. For a 65 kg woman, that’s roughly 65-78 g of protein a day, spread across meals.
• Bone strength depends on muscle that loads it. Sarcopenia and osteoporosis travel together; protein at every meal supports both.

Magnesium — check rather than supplement reflexively

• Supports parathyroid hormone function and bone matrix mineralisation.
• Routine class-level supplementation isn’t required. Worth checking the level if your calcium has run low repeatedly, if you’re on a long-term PPI, on a loop or thiazide diuretic, or have a GI absorption issue (coeliac, IBD, post-bariatric surgery).

Vitamin K2 (menaquinone) — modest evidence, conversation-based

• Supports osteocalcin carboxylation. Some RCT signal for bone mineral density in postmenopausal women; effect size is modest and AU guidelines don’t currently include it as a routine recommendation. Discuss case-by-case rather than blanket-recommend.

Weight-bearing and resistance training — independent fracture-risk reduction

• The medicine works on bone cells. Mechanical load works on the same bone — and on the muscle and balance that prevent the fall in the first place.
• Weight-bearing aerobic activity (brisk walking, dancing, jogging if appropriate, stair climbing) most days.
• Progressive resistance training 2-3 sessions per week — the load is what bone responds to. The LIFTMOR trial in postmenopausal women showed high-intensity resistance training improved bone density and was safe in supervised settings. An exercise physiologist or qualified personal trainer can help calibrate.

Falls prevention — the medicine works on bone, but the fracture begins with the fall

Most fragility fractures don’t happen in the gym. They happen on a rug, on a wet floor, on a step in the dark, after a quick blood-pressure drop on standing.

• Otago Exercise Programme — strength + balance training, well-evidenced for falls reduction in older adults.
• Tai chi — meta-analyses show meaningful falls reduction.
• Home hazard review — loose rugs, dim stairwells, slippery bathrooms, footwear.
• Vision check — when was your last optometry review?
• Medication review — sedatives, sleeping tablets, some blood-pressure medicines and antidepressants can increase falls risk. Worth periodically reviewing the list.
• Postural blood-pressure check — a drop on standing is a falls risk and is treatable.

Strontium ranelate — withdrawn

Strontium ranelate (Protelos / Protos) was used for osteoporosis in Australia until cardiovascular safety signals led to its withdrawal. Not a current option. Mentioned here only because some people still ask about it.

Earning a treatment holiday

After about 5 years on oral or 3 years on Aclasta, the conversation is whether to continue, hold, or switch. The factors that move that decision toward holding rather than continuing include: good DEXA trajectory, no interval fragility fracture, off any glucocorticoid that was driving the bone loss, stable falls risk, and your own preferences once the choice is laid out. The factors that point toward continuing are the opposite — sustained high T-score risk, ongoing steroids, falls, recent fracture.

This is genuinely a “we review it together” decision rather than a fixed rule.

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Track these between now and your next visit

• Any new persistent thigh, groin, or hip pain — when it started, which side, how it behaves with walking vs rest.
• Any new dental issues — non-healing socket, jaw pain, loose tooth, mouth swelling.
• For Aclasta in particular: any tingling around the mouth, in the hands or feet, or muscle cramps in the days after the infusion.
• Any new medicine or supplement you’ve started, including over-the-counter pain relief and any “bone health” supplement.
• Falls — any near-falls or actual falls since the last visit, and what was happening when it happened.

Bring the list to your review appointment.

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This is general information, not personal medical advice. Every patient is different. Decisions about your medicines — which one, what dose, when to stop, what to combine with — are made with the doctor who prescribed them. If anything on this page appears to contradict advice from your treating doctor, follow your doctor; they have context about your situation that this page cannot.

Reading this page does not establish a doctor-patient relationship with Dr Hoebing Lo. If you are not a current patient, please discuss your medicines with your own GP, specialist, or pharmacist.

About the integrative content. The lifestyle, dietary, and complementary recommendations on this page summarise current published research. Effect sizes are approximations from clinical studies — your individual response will vary, and real-world results are commonly smaller than trial results because day-to-day life differs from study conditions. Supplements and herbal products are not interchangeable with prescribed medication and can interact with it. Talk to your doctor and pharmacist before starting any new supplement, herbal product, or significant change in diet.

Currency. This page reflects clinical practice as of the last-reviewed date. Medicine evolves; specific details may date between reviews. Pricing shown is indicative; confirm with your pharmacist.

No commercial relationships. Dr Hoebing Lo has no financial or commercial relationship with the manufacturer of any medicine, brand, or supplement mentioned on this page.

Emergencies. If you have sudden swelling of face, lips, tongue, or throat; difficulty breathing; chest pain; severe dizziness or fainting; or new severe abdominal pain after starting a new medicine, call 000 or go to your nearest emergency department. Do not wait, and do not message us first.