How often should calcium and vitamin D levels be checked in patients on Evenity (romosozumab)?

Monitoring Calcium and Vitamin D in Patients on Evenity (Romosozumab)

Calcium and vitamin D levels should be checked before initiating Evenity therapy, then at least every 3 months during treatment. This monitoring schedule aligns with established guidelines for patients with bone metabolism disorders requiring close electrolyte monitoring.

Pre-Treatment Assessment

• Obtain baseline serum calcium and vitamin D (25-hydroxyvitamin D) levels
• Ensure calcium is within normal range (<9.5 mg/dL) before starting therapy
• Verify 25-hydroxyvitamin D levels are >30 ng/mL
• Correct any deficiencies before initiating Evenity

Monitoring Schedule During Treatment

First 3 Months:

• Check serum calcium monthly for the first 3 months after initiation 1
• Monitor serum phosphorus monthly for the first 3 months 1

Ongoing Monitoring:

• After first 3 months, check calcium and phosphorus at least every 3 months 1
• Measure 25-hydroxyvitamin D levels annually 1

Special Considerations

Romosozumab has been shown to cause modest but significant decreases in serum calcium (average 3.1% reduction after 1 month) 2. Certain patient factors increase risk of calcium fluctuations:

• Higher risk patients requiring more vigilant monitoring:
  • Older patients 2
  • Those with higher baseline calcium levels 2
  • Patients with renal impairment
  • Patients with malabsorption disorders 3

Management of Abnormal Values

• If calcium drops below 8.5 mg/dL:

  • Provide elemental calcium supplementation (1 g/day) 1
  • Consider vitamin D supplementation 1
  • Increase monitoring frequency to monthly until normalized

• If calcium exceeds 9.5 mg/dL:

  • Consider reducing calcium supplementation
  • Reassess in 2-4 weeks

• If vitamin D (25-OH) falls below 30 ng/mL:

  • Initiate vitamin D supplementation (ergocalciferol) 1
  • Recheck levels in 3 months

Practical Implementation

• Schedule laboratory tests 1-2 weeks before follow-up appointments
• Document calcium and vitamin D values at each visit
• Assess for symptoms of hypocalcemia (paresthesias, muscle cramps, tetany) at each visit
• Ensure adequate calcium (1000-2000 mg/day) and vitamin D (400-1200 IU/day) supplementation 4

Poor adherence to calcium and vitamin D supplementation is common, with studies showing only 31.2% of patients remain adherent after one year 3. Regular monitoring helps identify non-adherence and allows for timely intervention to maintain bone health during Evenity therapy.