Denosumab

What is denosumab?

Denosumab is used to treat osteoporosis. Osteoporosis is a condition that causes your bones to be thinner and weaker than normal. This means that they can break (fracture) easily, such as after a small bump or fall. Treatment with denosumab makes your bones stronger and less likely to break. Denosumab is generally only used when other medicines for osteoporosis have been unsuccessful. Read more about osteoporosis and treatment for osteoporosis. 

Denosumab comes as a pre-filled syringe which is given as an injection under your skin. 

Dose of denosumab

• The usual dose of denosumab is 60 mg given once every 6 months (2 times a year).
• Your doctor may prescribe calcium and vitamin D supplements (colecalciferol)  to help prevent low calcium levels in your blood while you take denosumab.
• Before you start denosumab, talk to your doctor about the expected length of time you will be taking it for, and what to do if you want to stop.

Precautions before taking denosumab

• Do you have problems with your kidneys?
• Are your pregnant or planning a pregnancy?
• Are you breastfeeding?
• Do you have low levels of calcium?
• Do you have any dental problems?

If so, it’s important that you tell your doctor before you start denosumab. Sometimes a medicine isn’t suitable for a person with certain conditions, or it can only be used with extra care. 

Contraception: If you are a women of childbearing age, you should use an effective method of birth control (contraception) during treatment with denosumab and for at least 5 months after your last dose of denosumab. Tell your doctor right away if you become pregnant while taking denosumab. 

Possible side effects from denosumab

Like all medicines, denosumab can cause side effects, although not everyone gets them. Often side effects improve as your body gets used to the new medicine.

Problems with your jaw

Denosumab can cause osteonecrosis of the jaw. This is a problem with your jaw that can be caused by delayed healing in your mouth after some dental procedures. This is quite rare. To reduce the risk of this problem, it is best to:

• maintain good hygiene and care of your teeth and mouth (such as brushing your teeth twice a day and regular flossing between your teeth)
• have regular dental check-ups
• let your dentist know that you are taking denosumab
• talk to your doctor or dentist if you have any loose teeth, tooth pain or swelling or numbness in your jaw.

Fractures

Denosumab can rarely cause fractures in your thigh bone (upper leg bone). These are called atypical fractures because they appear as cracks on the bone and are not usually related to an injury. If you have pain, weakness or discomfort in your thigh, hip or groin, tell your doctor. These pains may be warnings that there is some weakness in your bones. You may need x-rays of both your legs. 

If you stop treatment with this medicine, bone loss occurs, and there is a small chance that you may experience broken bones in your spine. If you wish to stop taking this medicine, talk to your doctor about your treatment options.

Other possible side effects

References

1. Denosumab New Zealand Formulary [accessed December 2019]
2. Prolia Medsafe Datasheet, August 2011

Additional resources for healthcare professionals

Risk of infections with Prolia (denosumab) Medsafe, NZ, 2020
Osteoporosis treatments and atypical femur fracture Medsafe, NZ, 2013
Osteonecrosis – a pain in the jaw Medsafe, NZ, 2012
Bisphosphonates – addressing the duration conundrum BPAC, NZ, 2019