Other Brands/Names

Actabone, Bonefos, Clodronate Disodium Tetrahydrate.

How It Works

Clodronic acid is a bisphosphonate that slows the breakdown of old or damaged bone (bone resorption). By inhibiting resorption, it helps prevent excessive release of calcium from bone into the bloodstream and maintains bone density. This effect is useful in conditions where resorption is increased, such as cancer-related hypercalcemia and osteoporosis.

Indications

This medicine is used for the following:

• Elevated blood calcium levels due to malignancies such as breast cancer
• Bone erosion caused by the spread of cancer cells to bone

Contraindication

Do not use this medicine in the following situations:

• Previous severe allergic reaction to bisphosphonates
• Active inflammatory bowel disease
• Pregnancy or breastfeeding
• In current treatment with another bisphosphonate
• Severe renal failure with creatinine clearance <10 mL/min (a test used to assess kidney function)

Side Effects

Both mild and serious effects can occur. Mild effects may include:

• Nausea
• Vomiting
• Diarrhea
• Itchy skin
• Redness and peeling of the skin
• Hypocalcemia in asymptomatic patients

Rare but serious effects may include:

• Symptomatic hypocalcemia
• Increased parathyroid hormone levels (which regulate calcium, phosphorus, and vitamin D)
• Worsening kidney function or kidney failure
• Respiratory failure

Types

Available forms include:

• 400 mg capsules
• Infusion solution vials
• Injectable ampoules 

Dosage

Doses are tailored to the patient’s condition. In patients with kidney disorderds (based on their creatinine clearance test results), the dose may be reduced by up to 50%.

• Increased blood calcium levels in cancer patients
  • Infusion
    • 300 mg daily infused over 2 hours until calcium normalizes (treatment duration of 7 days)
    • Alternatively, a single 1,500 mg dose infused over 4 hours
  • Tablets
    • Used to maintain normal calcium after IV therapy
    • 1,600–2,400 mg in one or two divided doses (maximum 3,200 mg per day)

• Bone erosion due to cancer metastasis
  
  • Initial dose is 1,600 mg in one or two divided doses; may increase per clinical need
  • Maximum dose is 3,200 mg per day

Safety

During pregnancy, clodronic acid crosses the placenta; harmful fetal effects have not been demonstrated, but use is not recommended in pregnancy or breastfeeding due to limited data on excretion into breast milk.

Drug Interactions

Clodronic acid can interact with other drugs and cause the following effects:

• Antacids and iron supplements may reduce clodronic acid absorption, lowering effectiveness.
• Increased risks of hypocalcemia increases when clodronic acid is given with: 
  • Aminoglycoside antibiotics
  • Diuretics
  • Calcitonin
  • Corticosteroids
  • Phosphates
• Concomitant NSAIDs (e.g., diclofenac sodium) may raise the risk of kidney disorders.

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