Sodium clodronate
Clasteon, Loron 520
Peer reviewed by Sid DajaniLast updated by Michael Stewart, MRPharmSLast updated 7 Aug 2023
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Do not eat food or have drinks containing milk during the two hours before you take a dose of sodium clodronate, or for one hour after taking a dose.
Do not let yourself become dehydrated - drink several large glassfuls of water each day.
If you buy any medicines or health remedies, you should ask a pharmacist to advise you. Some mineral preparations and antacid medicines will prevent sodium clodronate from working properly.
At a glance
Sodium clodronate is a bisphosphonate medication for bone problems.
It helps relieve bone pain in cancer and reduces high calcium levels caused by cancer.
Take doses at specific times, avoiding food and milk around doses.
Do not take other medicines for two hours before or one hour after sodium clodronate.
Maintain good dental hygiene and tell your dentist you are taking this medicine.
Speak to your doctor if you experience thigh pain, jaw pain, or ear pain.
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About sodium clodronate
Type of medicine | Bisphosphonate |
Used for | Bone pain in cancer; and to reduce high blood levels of calcium caused by cancer |
Also called | Clodronate disodium (in US); Clasteon®; Loron 520® |
Available as | Tablets and capsules |
Sodium clodronate is a bisphosphonate and is prescribed for problems which affect bones. It is prescribed to ease bone pain in people with cancer that has spread into the bone, and also to reduce hypercalcaemia associated with some cancers.
In some cancers there can be an excessive breakdown of bone. As this happens, calcium is lost from the bone and seeps into the blood, leading to higher than normal levels of calcium in the blood. This is called hypercalcaemia. Sodium clodronate binds to bone and reduces the rate at which it is broken down. This helps to strengthen bones and prevents the loss of calcium. This in turn reduces the high levels of calcium in the blood.
Before taking sodium clodronate
Back to contentsSome 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 sodium clodronate it is important that your doctor knows:
If you are pregnant or breastfeeding.
If you have recently had any inflammation of your digestive system such as an upset stomach or bowel.
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 taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, as well as herbal and complementary medicines.
If you have ever had an allergic reaction to a medicine.
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How to take sodium clodronate
Back to contentsBefore you start the treatment, read the manufacturer's printed information leaflet from inside the pack. It will give you more information about sodium clodronate and will provide you with a full list of the side-effects which you may experience from taking it.
Take sodium clodronate tablets/capsules exactly as your doctor tells you to. It is usual to be prescribed one or two doses to take each day. If you are prescribed one dose to take each day, take it first thing in the morning an hour before you have breakfast. If you are prescribed two doses a day, take your first dose an hour before breakfast and then take your second dose between meals (but see also the following advice).
Some foods and other medicines can interfere with how your body absorbs sodium clodronate and this will prevent the medicine from working as it should. Do not eat anything during the two hours before you take a dose, and also for one hour after taking a dose. It is particularly important that you avoid milk (including any drinks which contain milk) during this three-hour period. If you take other medicines, see the advice in the section below.
Try to take your doses of sodium clodronate at the same times of day each day. This will get you into a good daily routine and will help you avoid missing any doses.
If you do forget to take a dose, just take your next tablet/capsule at the usual time and continue as before. Do not take two doses together to make up for a missed dose.
Getting the most from your treatment
Back to contentsTry to keep your regular appointments with your doctor. This is so your doctor can check on your progress. You will need to have regular blood tests during treatment.
It is important that you do not become dehydrated during treatment with sodium clodronate. Your doctor will likely advise you to drink several large glassfuls of water each day. This is especially important in warm weather.
If you are taking any other medicines, do not take them during the two hours before you take sodium clodronate and wait for at least an hour afterwards before you take 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 sodium clodronate which your body absorbs and this will make your treatment less effective. Also, some painkillers called non-steroidal anti-inflammatory drugs (NSAIDs), can cause kidney problems when taken alongside sodium clodronate.
Good dental hygiene is particularly important while you are taking sodium clodronate - brush your teeth regularly and remember to have routine dental check-ups. Also, tell your dentist that you are taking sodium clodronate, as some dental treatments may not be recommended for you.
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Can sodium clodronate cause problems?
Back to contentsAlong 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 sodium clodronate. 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 sodium clodronate side-effects (these affect fewer than 1 in 10 people) | What can I do if I experience this? |
Feeling sick (nausea) or being sick (vomiting) | Stick to simple foods - avoid rich or spicy meals. If this becomes troublesome, speak with your doctor |
Diarrhoea | Drink plenty of water to replace any lost fluids. If this becomes troublesome, speak with your doctor |
Changes to some blood test results | Your doctor will monitor for these |
Less common, but possibly serious side-effects | What should I do if I experience this? |
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 |
Ear pain, discharge from an ear, ear infection | These could be signs of a problem called osteonecrosis of the ear. Speak with your doctor straightaway |
If you experience any other symptoms which you think may be due to the medicine, speak with your doctor or pharmacist for further advice.
How to store sodium clodronate
Back to contentsKeep all medicines out of the reach and sight of children.
Store in a cool, dry place, away from direct heat and light.
Important information about all medicines
Back to contentsImportant information about all medicines
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.
Report side effects to a medicine or vaccine
If you experience side effects, you can report them online through the Yellow Card website.

Unsure about mixing medicines?
Check for possible interactions between medicines, supplements and foods before taking them together.
Frequently asked questions
What is the main purpose of sodium clodronate for cancer patients?
Sodium clodronate is prescribed for cancer patients to relieve bone pain where cancer has spread to the bone. It also helps to lower very high levels of calcium in the blood, a condition known as hypercalcaemia, which can occur in some cancers.
How does sodium clodronate work to help my bones?
This medicine works by binding to your bones and slowing down the rate at which they are broken down. This process helps to make your bones stronger and prevents calcium from leaking out of them into your bloodstream, which in turn reduces high blood calcium levels.
Are there any specific foods or drinks I should avoid when taking sodium clodronate?
Yes, it is very important not to eat anything for two hours before taking a dose of sodium clodronate, and for one hour after taking it. During this three-hour period, you must particularly avoid milk and any drinks that contain milk, as these can interfere with how your body absorbs the medicine.
What should I do if I forget to take a dose of my medication?
If you miss a dose, you should simply take your next tablet or capsule at its usual scheduled time. Do not try to take two doses together to compensate for the missed one.
Why is dental hygiene so important while on this medication?
Maintaining good dental hygiene, including regular brushing and routine dental check-ups, is particularly important while taking sodium clodronate. You must also inform your dentist that you are taking this medicine, as some dental treatments might not be recommended for you.
What are some less common but serious side-effects I should be aware of?
While less common, some serious side-effects include pain in your thigh, hip, or groin, which could signal a thighbone fracture. Also, watch out for a loose tooth, jaw pain with swelling or numbness, as these can be signs of osteonecrosis of the jaw. Ear pain, discharge, or infection could indicate osteonecrosis of the ear. If you experience any of these, contact your doctor immediately.
Can I take other medicines, including over-the-counter ones, with sodium clodronate?
You should not take other medicines during the two hours before taking sodium clodronate and should wait at least an hour afterwards before taking them. Mineral supplements, iron preparations, and some indigestion remedies can reduce the effectiveness of sodium clodronate. Additionally, some painkillers called NSAIDs can cause kidney problems if taken with sodium clodronate. Always check with a pharmacist if buying over-the-counter medicines.
Further reading and references
- Medicines Complete BNF 89th Edition; British Medical Association and Royal Pharmaceutical Society of Great Britain, London.
- Manufacturer's PIL, Loron® 520 mg film-coated tablets; Esteve Pharmaceuticals (formerly Intrapharm Laboratories), The electronic Medicines Compendium. Dated June 2022.
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About the authorView full bio

Michael Stewart, MRPharmS
Medicine Leaflet Review Manager – Contractor, Pharmacist
BPharm (Hons), MRPharmS
Michael is a community pharmacist practicing in the Midlands and South Yorkshire with more than 20 years’ experience advising on medicines and medical conditions. He has a strong background in healthcare training, having produced and delivered training courses for pharmacy teams and staff of residential care settings, including nurses. He has also contributed to pharmacy advisory boards for the management of low acuity conditions in the community.
About the reviewer

Sid Dajani
Sultan Dajani qualified at the London School of Pharmacy in 1994 and became the youngest elected member of the Royal Pharmaceutical Society council since its founding in 1842.
Article history
The information on this page is written and peer reviewed by qualified clinicians.
Next review due: 6 Aug 2026
7 Aug 2023 | Latest version

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