Usage
- Strontium ranelate is prescribed for the treatment of severe osteoporosis in postmenopausal women and adult men at high risk of fracture, particularly when other osteoporosis treatments are unsuitable due to contraindications or intolerance. It reduces the risk of vertebral and hip fractures.
- Pharmacological classification: Dual-action bone agent (DABA), anti-osteoporotic.
- Mechanism of Action: Strontium ranelate has a dual effect on bone metabolism. It stimulates bone formation by promoting osteoblast precursor replication and collagen synthesis. Simultaneously, it decreases osteoclast differentiation and resorbing activity, thus reducing bone resorption. This dual action results in a rebalancing of bone turnover in favor of bone formation.
Alternate Names
- International Nonproprietary Name (INN): Strontium ranelate
- Brand Names: Protelos, Protos, Osseor, Onita
How It Works
- Pharmacodynamics: Strontium ranelate increases bone formation and decreases bone resorption. It integrates into the bone matrix, replacing calcium, and increases bone mineral density. The exact mechanisms through which it affects osteoblasts and osteoclasts are not fully elucidated but are thought to involve calcium-sensing receptors and other pathways related to bone remodeling.
- Pharmacokinetics:
- Absorption: Oral absorption is relatively slow and reduced by food, milk, and calcium-containing products. Absolute bioavailability is approximately 25%.
- Distribution: Volume of distribution is around 1 L/kg. Strontium has a low plasma protein binding (25%) and a high affinity for bone tissue. It doesn’t accumulate in non-calcified tissues.
- Metabolism: Strontium ranelate is not metabolized.
- Elimination: Excreted via the kidneys and the gastrointestinal tract. The effective half-life is around 60 hours.
Dosage
Standard Dosage
Adults:
- 2 g once daily, administered orally at bedtime, preferably at least two hours after eating. The granules should be mixed with water and drunk immediately after preparation, even though they remain stable in suspension for 24 hours.
Children:
- The safety and efficacy of strontium ranelate have not been established in children under 18 years of age. No data are available for pediatric use.
Special Cases:
- Elderly Patients: No dose adjustment is necessary.
- Patients with Renal Impairment: No dose adjustment is needed for mild to moderate renal impairment (creatinine clearance 30-70 mL/min). Strontium ranelate is not recommended for patients with severe renal impairment (creatinine clearance < 30 mL/min).
- Patients with Hepatic Dysfunction: No dose adjustment is required.
- Patients with Comorbid Conditions: Use with caution in patients at risk of venous thromboembolism. Patients with uncontrolled hypertension or a history of ischemic heart disease, peripheral arterial disease, or cerebrovascular disease should not take strontium ranelate.
Clinical Use Cases
Strontium ranelate is not indicated for use in clinical settings like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations. Its use is specifically for long-term management of osteoporosis.
Side Effects
Common Side Effects
- Nausea
- Diarrhea
- Headache
- Skin irritation (eczema, dermatitis)
Rare but Serious Side Effects
- Venous thromboembolism (VTE)
- Hypersensitivity reactions (angioedema, rash, urticaria, pruritus)
- Seizures
- Memory loss
- Confusion
- Toxic epidermal necrolysis
- Stevens-Johnson syndrome
- Drug reaction with eosinophilia and systemic symptoms (DRESS)
Long-Term Effects
Potential for a small increased risk of blood clots with extended use.
Contraindications
- Hypersensitivity to strontium ranelate
- Current or previous venous thromboembolic events
- Temporary or permanent immobilization (e.g., post-surgical recovery, prolonged bed rest)
- Current or history of ischemic heart disease, peripheral arterial disease, or cerebrovascular disease
- Uncontrolled hypertension
- Severe renal impairment (creatinine clearance < 30 mL/min)
- Pregnancy and breastfeeding
Drug Interactions
- Calcium-containing products (food, supplements, medications): Reduce strontium ranelate bioavailability. Administer strontium ranelate at least two hours before or after these products.
- Oral tetracycline and quinolone antibiotics: Strontium may reduce the absorption of these antibiotics. Simultaneous administration is not recommended. Suspend strontium ranelate treatment during antibiotic therapy.
- Aluminum and magnesium hydroxides (antacids): May slightly decrease strontium absorption. Take antacids at least two hours after strontium ranelate, although concomitant intake at bedtime is acceptable if separate dosing is impractical.
- Raltegravir: Strontium may chelate with raltegravir and reduce its absorption. Separate administration by at least 4 hours.
Pregnancy and Breastfeeding
- Pregnancy Safety Category: Strontium ranelate is contraindicated in pregnancy. There are no data on its use in pregnant women. Animal studies at high doses showed reversible bone effects in offspring.
- Breastfeeding: Strontium ranelate is contraindicated during breastfeeding. It is excreted in human milk.
Drug Profile Summary
- Mechanism of Action: Dual-action bone agent: increases bone formation and decreases bone resorption.
- Side Effects: Nausea, diarrhea, headache, skin irritation; rarely, VTE, hypersensitivity reactions, seizures.
- Contraindications: Hypersensitivity, VTE history, immobilization, severe renal impairment, pregnancy, breastfeeding, uncontrolled hypertension.
- Drug Interactions: Calcium, tetracyclines, quinolones, antacids, raltegravir.
- Pregnancy & Breastfeeding: Contraindicated.
- Dosage: 2g orally once daily at bedtime.
- Monitoring Parameters: Renal function (in patients with chronic renal impairment), cardiovascular health (especially in those with risk factors for VTE).
Popular Combinations
Calcium and vitamin D supplements are often prescribed with strontium ranelate if dietary intake is inadequate. However, they should be taken separately, at least two hours apart from strontium ranelate administration.
Precautions
- Assess renal function periodically in patients with chronic renal impairment.
- Monitor for signs and symptoms of VTE.
- Monitor cardiovascular health, especially in patients with risk factors for VTE.
- Avoid concomitant use with tetracycline and quinolone antibiotics.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Strontium Ranelate?
A: 2 g once daily at bedtime, at least two hours after food or calcium-containing products.
Q2: How should Strontium Ranelate be taken?
A: The granules should be mixed in at least 30ml of water and drunk immediately. They don’t dissolve completely, resulting in a cloudy suspension.
Q3: Can Strontium Ranelate be used during pregnancy or breastfeeding?
A: No, it is contraindicated in both pregnancy and breastfeeding.
Q4: What are the common side effects of Strontium Ranelate?
A: The most common side effects are nausea, diarrhea, and headache, which are typically mild and transient.
Q5: What are the serious side effects of Strontium Ranelate?
A: Rare but serious side effects include venous thromboembolism, hypersensitivity reactions, seizures, and skin reactions like toxic epidermal necrolysis and Stevens-Johnson syndrome.
Q6: How does Strontium Ranelate interact with calcium supplements?
A: Calcium reduces the bioavailability of strontium ranelate. Take calcium supplements at least two hours apart from strontium ranelate.
Q7: Can Strontium Ranelate be used in patients with renal impairment?
A: It can be used in patients with mild to moderate renal impairment without dose adjustment, but is not recommended in patients with severe renal impairment.
Q8: Can Strontium Ranelate be used with other osteoporosis medications?
A: It is generally reserved for patients who cannot tolerate or have contraindications to other osteoporosis treatments. Discuss potential drug interactions with a physician before combining strontium ranelate with other medications.
Q9: What should patients be advised about regarding lifestyle while taking Strontium Ranelate?
A: Patients should ensure adequate calcium and vitamin D intake through diet or supplementation if necessary. They should also be counseled on the importance of regular exercise and fall prevention strategies. Smoking cessation and limiting alcohol consumption are also beneficial for bone health.
This information is current as of February 17, 2025, and is intended for use by qualified medical professionals. Always consult the latest prescribing information and clinical guidelines before making treatment decisions.
