Alendronic acid for osteoporosis - Fosamax

It is very important that you carefully follow the instructions for taking alendronic acid - otherwise it can cause irritation and damage to your throat. You will find full instructions on the information leaflet provided with your medicine. See also the section called 'Taking alendronic acid', below.

If you buy any medicines, make sure your pharmacist knows that you are taking a bisphosphonate, as some medicines will prevent alendronic acid from working properly.

Good dental hygiene is particularly important with this treatment - this means that you must brush your teeth regularly, and have routine dental check-ups.

Type of medicine Bisphosphonate
Used for Osteoporosis
Also called Sodium alendronate
Brands: Fosamax®; Fosamax® Once Weekly
Combination brand: Fosavance® (alendronic acid with colecalciferol/vitamin D3)
Available as Tablets and oral liquid

Osteoporosis is a bone disease which causes your bones to become brittle and fragile, making them prone to breaks and fractures. During our lifetime, old bone tissue is constantly being broken down and replaced by new bone. After the age of about 30-35 years, our bone begins to lose density because old bone is lost faster than new bone can replace it. Women in particular have an increased risk of developing osteoporosis, as they lose bone material rapidly after the menopause.

Alendronic acid belongs to a group of medicines known as bisphosphonates. These medicines slow down the rate at which old bone is lost. As your body continues to make new bone, this leads to an overall increase in bone density. This reduces your risk of broken bones and fractures. You may be prescribed alendronic acid to take once a day (10 mg strength tablets), or alternatively once a week (70 mg strength tablets/medicine).

In a brand of tablet called Fosavance®, alendronic acid is combined with a supplement of a vitamin called colecalciferol (also known as vitamin D3). Colecalciferol helps your bones absorb calcium. Because our bodies naturally make colecalciferol from exposure to sunlight and also absorb small amounts from foods such as oily fish, many people do not need supplements of this vitamin. However, as we get older, the amount of colecalciferol we absorb naturally may reduce. This brand of tablet is suitable for people requiring supplements of colecalciferol alongside alendronic acid.

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you start taking alendronic acid it is important that your doctor knows:

  • If you are pregnant or breast-feeding.
  • If you have ever had any difficulties swallowing.
  • If you have had a stomach ulcer, stomach bleeding or any surgery on your upper digestive system within the last year.
  • If you are due to have any dental treatment in the near future, or if you have not recently had a dental check-up.
  • If you have any problems with the way your kidneys work.
  • If you are unable to sit upright for at least 30 minutes.
  • If you have been told you have low amounts of calcium in your blood.
  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.
  • If you have ever had an allergic reaction to a medicine.
  • Before you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about alendronic acid and will provide you with a full list of the side-effects which you may experience from taking it.
  • If you are taking alendronic acid 10 mg tablets, take one tablet daily. If on any day you forget to take a dose, just take your tablet on the next day as usual. Do not take a double dose to make up for a missed dose.
  • If you are taking tablets containing alendronic acid 70 mg (brands Fosamax® Once weekly and Fosavance®), take one tablet once a week. You must take your dose on the same day of each week, so choose a day that best suits your routine. If you forget to take a dose on your usual day, take it on the following morning and then continue taking it on your chosen day when your next dose is due.
  • If you are taking alendronic acid 70 mg in 100 ml oral liquid medicine, take 100 ml (one unit) once a week. Take it on the same day of each week. If you forget to take a dose on your usual day, take it on the following morning and then continue taking it on your chosen day when your next dose is due.

Taking alendronic acid

It is important that you take alendronic acid in the correct way, as otherwise it can cause irritation and damage as it is swallowed:

  • Take the tablet/medicine first thing after getting up in the morning. Take it before you eat any food or have anything to drink other than water.
  • You must drink a large glassful of plain water (not mineral water) as you take your dose. If you are taking tablets, swallow the tablet whole - you must not chew, break, or crush alendronic acid tablets.
  • It is important that you take your dose while you are standing or sitting in an upright position.
  • Continue to sit or stand upright for 30 minutes after taking your dose - you must not lie down during this time.
  • Do not have anything to eat or drink (other than plain water) during the 30 minutes after taking a dose.
  • Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress. It is likely you will need to have regular blood tests during this treatment.
  • If you are taking other medicines, wait at least 30 minutes after taking alendronic acid before taking your other medicines. If you buy any medicines 'over-the-counter', check with a pharmacist that they are suitable for you to take. This is because mineral supplements, iron preparations, and some indigestion remedies reduce the amount of alendronic acid which your body absorbs. This can make your treatment less effective.
  • Good dental hygiene is particularly important while you are taking alendronic acid - brush your teeth regularly and remember to have routine dental check-ups. Tell your dentist that you are taking alendronic acid, as some dental treatments may not be recommended for you.
  • Eating a well-balanced diet and taking regular exercise can help your bones stay strong. Remember to follow any exercise or dietary advice that your doctor gives to you.
  • Chemicals from tobacco can get into your bloodstream and can affect your bones, making bone loss worse. If you are a smoker, you should try to quit if possible. Ask your doctor or pharmacist for advice on how to stop smoking.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with alendronic acid. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.

Common alendronic acid side-effects (these affect less than 1 in 10 people) What can I do if I experience this?
Indigestion, abdominal pain, bloating, wind, acid regurgitation, feeling sick Make sure you carefully follow the directions for taking alendronic acid and remain standing or sitting for at least half an hour afterwards. If the symptoms get worse, let your doctor know straightaway
Diarrhoea Drink plenty of water to replace lost fluids
Constipation Try to eat a well-balanced diet and drink several glasses of water a day
Headache, muscle or joint pain Ask your pharmacist to recommend a suitable painkiller
Feeling dizzy, itching If troublesome, speak with your doctor
Less common, but possibly serious, side-effects What should I do if I experience this?
Heartburn, pain or difficulty when you swallow Stop taking alendronic acid and speak with your doctor as soon as possible - these can be signs of severe throat irritation
Pain in your thigh, hip, or groin Speak with your doctor as soon as possible - these can be signs of a thighbone fracture
A loose tooth, or jaw pain with swelling or numbness Speak with your doctor as soon as possible - these can be signs of a problem called osteonecrosis of the jaw
Black or bloody stools Speak with your doctor as soon as possible - this can be a sign of an ulcer

If you experience any other symptoms which you think may be due to the medicine, speak with your doctor or pharmacist for further advice.

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital at once. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Further reading & references

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Helen Allen
Current Version:
Peer Reviewer:
Dr Helen Huins
Document ID:
3626 (v26)
Last Checked:
16/06/2014
Next Review:
15/06/2017
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