Description

Strontium Ranelate is a medication used for the treatment of osteoporosis. It is a salt of strontium and ranelic acid. Its unique pharmacological profile is due to its active component, the strontium ion, which is absorbed from the gastrointestinal tract and incorporates into the bone crystal lattice. Strontium Ranelate is distinguished from other osteoporosis treatments by its dual mechanism of action. It is available as an oral granular powder that is dissolved in water.

Indication

Strontium Ranelate is indicated for the treatment of severe osteoporosis. Its main indications include:

• Postmenopausal Osteoporosis: It is used to reduce the risk of vertebral and hip fractures in postmenopausal women with severe osteoporosis.

• Osteoporosis in Men: It is also indicated for men at increased risk of fracture.

Due to a small risk of serious cardiovascular events, its use is now generally restricted to patients with severe osteoporosis who cannot be treated with other therapies, such as bisphosphonates. It is contraindicated in patients with a history of cardiovascular disease, uncontrolled hypertension, or ischemic heart disease.

Mechanism of Action

Strontium Ranelate’s mechanism of action is unique in that it has a dual effect on bone metabolism, simultaneously promoting bone formation and inhibiting bone resorption.

1. Stimulation of Bone Formation:
   • The strontium ion, which is chemically similar to calcium, is incorporated into the bone crystal lattice at a ratio that mimics the natural bone mineral.

• • Strontium stimulates the proliferation and differentiation of osteoblasts, the cells responsible for building new bone tissue.

• • It also promotes the synthesis of collagen, the protein matrix of bone, upon which the bone mineral is deposited.

• • By stimulating osteoblast activity, strontium ranelate increases the rate of bone formation.

2. Inhibition of Bone Resorption:
   • Strontium also has an inhibitory effect on osteoclasts, the cells that break down bone.

• • It is believed to inhibit the differentiation of osteoclast precursors into mature, bone-resorbing osteoclasts.

• • It also reduces the resorptive activity of mature osteoclasts by disrupting their cellular processes.

• • By inhibiting osteoclast activity, strontium ranelate reduces the rate of bone breakdown.

The net effect of these two actions is a shift in the balance of bone remodeling towards bone formation, leading to a significant increase in bone mineral density and a reduction in fracture risk. Unlike bisphosphonates, which primarily inhibit resorption, strontium ranelate both builds and strengthens bone by its dual mechanism.