Alendronate (alendronic acid)

(Brand names: Fosamax®, Fosavance®, Binosto®)

Alendronate is an osteoporosis medication. It belongs to a group of drugs called bisphosphonates, which are the most commonly used treatment for people with osteoporosis. Bisphosphonates are often the first treatment you'll be offered if you have weaker bones.

Alendronate works by slowing down the cells that break down bone. This can help strengthen your bones and reduce your risk of breaking a bone.

Alendronate won't help to reduce the pain caused by broken bones. But there are other treatments and ways to relieve pain if this is a problem for you.

Download our fact sheet

We've heard that some people are having problems getting alendronic acid 70mg tablets. This is because some companies that make these tablets have run out of stock. This shortage may last until September 2022.

If you're about to start treatment

If you're about to start a bone-strengthening medication for the first time and can't get alendronate, talk to your doctor or pharmacist about other treatment options. They may offer to prescribe another bisphosphonate, such as risedronate, or a different type of treatment given as an injection.

It's important not to delay starting a treatment, particularly if tests have shown your risk of breaking a bone is very high.

If you usually take alendronate tablets

If you can't get your usual tablets, speak to your local pharmacist. There are a few possible options. Don't worry if it takes a few weeks to organise – the effect of your treatment will wear off slowly.

  • Speaking to their suppliers. Your pharmacist may be able to get alendronate tablets from a different supplier, as not all companies that make alendronate tablets have run out of stock.
  • A different form of alendronate. If your pharmacist can't get alendronate tablets at all, ask about having a different form of alendronate. For example, you may be able to get alendronate as a liquid that you swallow, or as a tablet that you dissolve in water and drink. You could then switch back to your usual tablets when supplies are normal again.
  • A similar medication. You may be offered a different bisphosphonate, such as risedronate. This is similar to alendronate and is also taken once a week.
  • A treatment break. If you've been taking alendronate for five years or more, it may be fine to stop taking it for a year or two. Your doctor or pharmacist will only suggest this if it's safe for you – this will depend on things like your age, bone mineral density (BMD), and any broken bones you've had. The benefits of your alendronate will continue for a while after you stop taking it. But you'll need to start taking it again at some point. You should discuss this with your doctor, so that you know when to start again.


Who can have alendronate?

Alendronate is usually offered to postmenopausal women and men. It is occasionally given to younger women.


When is alendronate not suitable?

Alendronate isn't suitable for everyone. It may not be the best treatment if you:

  • have a condition called Barrett’s oesophagus
  • have severe kidney problems
  • are pregnant or breastfeeding
  • have difficulty swallowing tablets.


What does treatment involve?

Alendronate is available as:

  • a weekly tablet
  • a tablet that you dissolve in water and drink
  • a liquid that you swallow.


When to take it

For both the tablet and liquid that you swallow, it's very important to take alendronate on an empty stomach. This is so that your body can absorb the medication properly.

Take it first thing in the morning, and wait at least 30 minutes before having any food, drink or other medication – although you can drink water.

Try to wait at least four hours after taking alendronate before taking a calcium supplement. Calcium can affect how the medication is absorbed.

It's important to take your alendronate regularly, as advised by your doctor or pharmacist.


If you miss a dose

Missing the odd dose is unlikely to affect your overall bone health, but you should try to avoid it.

If you often forget or struggle to take your medication, speak to your doctor about other treatment options. There may be something that suits you better.


How long to take it

Alendronate is usually prescribed for several years or more, so make sure it's the right decision for you.

Your doctor should review your treatment with you after five years. This is to make sure the benefits of taking alendronate still outweigh any possible risks.

At your treatment review, your doctor may recommend that you keep taking alendronate. If suitable, they may suggest a 'treatment break', where you stop taking alendronate for a while before starting it again. Or they may advise you to stop taking alendronate for good.


If you're prescribed alendronate

Get all the information you need

Find out about your treatment options so that you can be fully involved in decisions and know what to expect. Talk to your doctor about your medication, its side effects and any risks. You can read more about these below.

It’s important to read the information in the patient information leaflet that comes with your treatment. You can also read more detailed information in our fact sheet.

Our specialist nurse Helpline is here for you, if you have any questions or concerns.


Know how to lower your risk of side effects and other problems

Like all treatments, alendronate can cause side effects, but these aren’t very common. They can include:

  • inflamed food pipe, sore throat, difficulty swallowing, or heartburn
  • bone, joint or muscle pain
  • diarrhoea (frequent or runny bowel movements)
  • constipation (difficulty emptying your bowels)
  • headache
  • inflammation in the eye, eye pain, or sight problems.

If you do get side effects, they shouldn't last for long. Speak to your doctor or pharmacist, as they may be able to help you manage them. There's also more information in our fact sheet.

If you notice any other problems or changes, check the patient information leaflet that comes with your alendronate. They may be side effects of your alendronate, or they may be caused by something else, such as another medication. If you're worried or unsure, speak to your doctor or pharmacist.


Other possible health risks

Alendronate can, very rarely, cause some more serious health problems.

It's natural to feel concerned about these – but your risk of getting either problem is very small. If your doctor has prescribed alendronate, this means they are confident that the benefit for your bones outweighs any risks.

Do speak to them about any concerns you have. They can help you understand more about your risk of these very uncommon problems, as well as what could happen if you don't take a bone-strengthening medication. Our specialist nurses are also here for you.


Content reviewed: August 2017

(updated July 2022)


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