How Prolia Works

The body features an ongoing process called bone remodeling where bones are constantly broken down (bone resorption) and rebuilt. Bones are broken down by a type of cell called osteoclasts and are built back up by a type of cell called osteoblasts.

In patients with osteoporosis, too much bone is being broken down too quickly.

Before osteoclasts mature and are able to break down bone, they are called pre-osteoclasts. These pre-osteoclasts have a specific receptor on their cell surface called RANK (receptor activator of nuclear factor-kappa B). When RANK is switched on by a protein called RANKL (RANK-Ligand), it causes the pre-osteoclasts to mature into bone-dissolving osteoclasts.

Prolia is a protein called a monoclonal antibody that binds to RANKL. This prevents the RANKL from binding to pre-osteoclasts, and thus prevents them from maturing into osteoclasts. The effect is that the bone resorption process is slowed down, and the body has more time to build up and strengthen its bones.

The body makes a substance called osteoprotegerin that does a similar thing to Prolia by preventing pre-osteoclasts from maturing into osteoclasts. In some patients with osteoporosis, this substance is found in lower concentrations and this is partly why their bones break down too quickly.

Side Effects of Prolia

Patients taking Prolia should talk to their doctor if they are concerned about any side effects.

The most common side effect of this medication are rashes and issues with the skin.

Patients should let their doctor know if they develop a rash while taking Prolia, develop jaw pain, or experience muscle cramps, twitching or weakness.

Possible side effects include:

  • Rash – Prolia can cause a rash, itching, or dry skin.
  • Muscle & bone pain – Prolia can cause bone, muscle, or joint pain
  • Low calcium – the medication can very rarely lower the calcium in the blood. Patients should tell their doctor if they develop:
    • Tingling in the hands, feet, or around the mouth
    • Muscle cramps or twitching
    • Muscle weakness
  • Jaw problem – Prolia has very rarely been associated with a jaw problem called osteonecrosis

Prolia should not be taken during pregnancy or breastfeeding. Patients who become pregnant should stop taking this medication and contact their doctor.

Who Should NOT Take Prolia

People who should NOT take Prolia include:

  • Those allergic to Prolia or any ingredient in the medicine
  • Pregnant or breast-feeding women

Anyone who becomes pregnant while taking Prolia should notify their doctor immediately.

When to Call a Doctor

Patients taking Prolia should call their doctor if they feel sick and want to stop, or if they are concerned about any side effects.

Other reasons to call a doctor while taking Prolia include:

  • Tingling in hands, feet or around mouth
  • Becoming pregnant or planning pregnancy
  • New severe pain in the jaw
  • Muscle cramps, pain, or weakness
  • Fever or possible infection

Prolia Video

Watch Dr. Andy Thompson, a Canadian rheumatologist, introduce Prolia.