Strontium ranelate, a strontium(II)

salt In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ...

of ranelic acid, is a medication for

osteoporosis Osteoporosis is a systemic skeletal disorder characterized by low bone mass, micro-architectural deterioration of bone tissue leading to more porous bone, and consequent increase in Bone fracture, fracture risk. It is the most common reason f ...

marketed as Protelos or Protos by

Servier Servier Laboratories (French: Laboratoires Servier, often abbreviated to Servier) is an international Pharmaceutical industry, pharmaceutical company governed by a non-profit foundation, with its headquarters in France (Suresnes). The consolida ...

. Studies indicate it can also slow the course of

osteoarthritis Osteoarthritis is a type of degenerative joint disease that results from breakdown of articular cartilage, joint cartilage and underlying bone. A form of arthritis, it is believed to be the fourth leading cause of disability in the world, affect ...

of the knee. The drug is unusual in that it both increases deposition of new bone by

osteoblast Osteoblasts (from the Greek combining forms for " bone", ὀστέο-, ''osteo-'' and βλαστάνω, ''blastanō'' "germinate") are cells with a single nucleus that synthesize bone. However, in the process of bone formation, osteoblasts fu ...

s and reduces the resorption of bone by

osteoclast An osteoclast () is a type of bone cell that breaks down bone tissue. This function is critical in the maintenance, repair, and bone remodeling, remodeling of bones of the vertebrate, vertebral skeleton. The osteoclast disassembles and digests th ...

s. It is therefore promoted as a "dual action bone agent" (DABA). On 13 May 2013, Servier released a Direct Healthcare Professional Communication which stated that new restrictions for the use of strontium ranelate are now in place, as randomised trials have shown an increased risk of

myocardial infarction A myocardial infarction (MI), commonly known as a heart attack, occurs when Ischemia, blood flow decreases or stops in one of the coronary arteries of the heart, causing infarction (tissue death) to the heart muscle. The most common symptom ...

. Servier states that the use is now restricted to treatment of severe osteoporosis in postmenopausal women at high risk for fracture. The European Pharmacovigilance Risk Assessment Committee (PRAC) recommended restriction in the use of strontium ranelate, based on a routine benefit-risk assessment of the medicine, which included data showing a possible increased risk of heart problems, including heart attacks. On 21 February 2014 the European Medicine Agency recommended that strontium ranelate remain available with restrictions relative to patients with existing heart disease. In 2017, a large study of over 280,000 British and Spanish patients found no increased risk of venous thromboembolism in users of strontium ranelate compared to alendronate. Servier ceased manufacturing the drug and in 2019, the drug returned the market in the United Kingdom under the name strontium ranelate Aristo.

Uses

Strontium ranelate is registered as a prescription drug in more than 70 countries for the treatment of post- menopausal

to reduce the risk of vertebral and hip fractures. In the United States, strontium ranelate is not approved by the

FDA The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...

. In the United Kingdom, strontium ranelate is prescribed under the

National Health Service The National Health Service (NHS) is the term for the publicly funded health care, publicly funded healthcare systems of the United Kingdom: the National Health Service (England), NHS Scotland, NHS Wales, and Health and Social Care (Northern ...

as a medicine for the treatment of post menopausal osteoporosis. 2 major phase III clinical studies, SOTI (Spinal Osteoporosis Therapeutic Intervention) and TROPOS (Treatment of Peripheral Osteoporosis), were started in 2000 to investigate the efficacy of strontium ranelate in reducing vertebral fractures and peripheral fractures, including hip fractures. In the 3 years results, reported in 2004, strontium ranelate showed significant reduction in vertebral fractures with 41% and hip fractures with 36% compared with patients treated with placebo. The efficacy was sustained in 5 years data. The 5 years data confirmed that strontium ranelate can reduce the vertebral fractures significantly no matter the risk factors of the osteoporotic women have. These include their age (<70, 70–80 and >80),

bone mineral density Bone density, or bone mineral density, is the amount of bone mineral in bone tissue. The concept is of mass of mineral per volume of bone (relating to density in the physics sense), although clinically it is measured by proxy according to opti ...

(osteoporotic and osteopenia), prevalent fractures (0 prevalent fracture, 1–2 prevalent fractures and >2 prevalent fractures), symptomatic fractures,

body mass index Body mass index (BMI) is a value derived from the mass (Mass versus weight, weight) and height of a person. The BMI is defined as the human body weight, body mass divided by the square (algebra), square of the human height, body height, and is ...

and smoking. Strontium ranelate shows anti-fracture efficacy in very old elderly and osteopenic patients.

Contraindications

Strontium ranelate is contraindicated in hypersensitivity to the active substance or to any of the excipients. It is not recommended in patients with severe renal disease, i.e. creatinine clearance below 30 mL/min due to lack of data. Precaution is advised in patients at increased risk of

venous thromboembolism Venous thrombosis is the blockage of a vein caused by a thrombus (blood clot). A common form of venous thrombosis is deep vein thrombosis (DVT), when a blood clot forms in the deep veins. If a thrombus breaks off ( embolizes) and flows to the lun ...

(VTE), including patients with a history of VTE. Precaution is advised in patients with

phenylketonuria Phenylketonuria (PKU) is an inborn error of metabolism that results in decreased metabolism of the amino acid phenylalanine. Untreated PKU can lead to intellectual disability, seizures, behavioral problems, and mental disorders. It may also r ...

, as formulations of strontium ranelate contain phenylalanine. Precaution as it interferes with colorimetric measurements of calcium in blood and urine.

Side effects

Available data do not show evidence of an increased cardiovascular risk in patients without established, current or past history of ischaemic heart disease, peripheral arterial disease or cerebrovascular disease, or in those without uncontrolled hypertension. In a meta-analysis of 7,500 patients, in those with known uncontrolled or severe cardiovascular disease, strontium ranelate increased the risk of venous thromboembolism, pulmonary embolism and serious cardiovascular disorders, including myocardial infarction as compared with placebo (1.7% versus 1.1%). Its use is restricted in the UK to those without severe cardiovascular disease. The most common side effects include

nausea Nausea is a diffuse sensation of unease and discomfort, sometimes perceived as an urge to vomit. It can be a debilitating symptom if prolonged and has been described as placing discomfort on the chest, abdomen, or back of the throat. Over 30 d ...

diarrhea Diarrhea (American English), also spelled diarrhoea or diarrhœa (British English), is the condition of having at least three loose, liquid, or watery bowel movements in a day. It often lasts for a few days and can result in dehydration d ...

headache A headache, also known as cephalalgia, is the symptom of pain in the face, head, or neck. It can occur as a migraine, tension-type headache, or cluster headache. There is an increased risk of Depression (mood), depression in those with severe ...

and

eczema Dermatitis is a term used for different types of skin inflammation, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened ...

, but with only 2–4% increase compared with placebo group. Most of those side effects resolved within 3 months. Occasional severe allergic reactions have been reported including drug rash with eosinophilia and systemic symptoms ( DRESS syndrome)

Interactions

According to the manufacturer, strontium ranelate should be taken 2 hours before antacids and 2 hours apart from food, milk and derivative products, and medicinal products containing calcium. Treatment should be suspended while taking oral

tetracycline Tetracycline, sold under various brand names, is an antibiotic in the tetracyclines family of medications, used to treat a number of infections, including acne, cholera, brucellosis, plague, malaria, and syphilis. It is available in oral an ...

and

quinolone antibiotic Quinolone antibiotics constitute a large group of broad-spectrum bacteriocidals that share a bicyclic core structure related to the substance 4-quinolone. They are used in human and veterinary medicine to treat bacterial infections, as wel ...

s, as these

chelate Chelation () is a type of bonding of ions and their molecules to metal ions. It involves the formation or presence of two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central metal atom. These l ...

the strontium ion.

Pharmacology

Mechanism of action

Strontium, which has the

atomic number The atomic number or nuclear charge number (symbol ''Z'') of a chemical element is the charge number of its atomic nucleus. For ordinary nuclei composed of protons and neutrons, this is equal to the proton number (''n''p) or the number of pro ...

38, belongs to group II in the periodic table of elements, just beneath

calcium Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to it ...

. Because its nucleus is very nearly the same size as that of calcium, the body easily takes up strontium and incorporates it into bones and tooth enamel in place of calcium. This is not a health problem, and in fact, it can provide a health benefit. For example, in clinical trials, the drug strontium ranelate was found to aid bone growth, increase bone density, and lessen vertebral, peripheral, and hip fractures in women. Strontium ranelate is an antiosteoporotic agent which both increases bone formation and reduces bone resorption, resulting in a rebalance of bone turnover in favor of bone formation. This is similar to the effects of choline-stabilized orthosilicic acid. Strontium ranelate stimulates the calcium-sensing receptors and leads to the differentiation of pre-osteoblast to

which increases the bone formation. Strontium ranelate also stimulates osteoblasts to secrete

osteoprotegerin Osteoprotegerin (OPG), also known as osteoclastogenesis inhibitory factor (OCIF) or tumour necrosis factor receptor superfamily member 11B (TNFRSF11B), is a cytokine receptor of the tumour necrosis factor (TNF) receptor superfamily encoded by th ...

in inhibiting

osteoclasts An osteoclast () is a type of bone cell that breaks down bone tissue. This function is critical in the maintenance, repair, and remodeling of bones of the vertebral skeleton. The osteoclast disassembles and digests the composite of hydrated ...

formed from pre-osteoclasts in relation to the

RANKL Receptor activator of nuclear factor kappa- ligand (RANKL), also known as tumor necrosis factor ligand superfamily member 11 (TNFSF11), TNF-related activation-induced cytokine (TRANCE), osteoprotegerin ligand (OPGL), and osteoclast differentiat ...

system, which leads to the decrease of bone resorption.

Research

A large international study, the "Strontium Ranelate Efficacy in Knee Osteoarthritis trial," or SEKOIA, reported in 2012 that the drug significantly slowed the course of knee OA compared to placebo in a double-blind randomised controlled trial. The drug reduced knee OA pain symptoms, improved function, and reduced x-ray detectable cartilage loss, as shown by reductions in joint space narrowing over three years.

References

External links

*< * *
Protelos official site
* {{Drugs for treatment of bone diseases Osteoporosis drugs Strontium compounds