Do you order creatine kinase (CK) levels for patients on daptomycin?

Monitoring Creatine Kinase (CK) for Patients on Daptomycin

Yes, you should monitor creatine kinase (CK) levels in all patients receiving daptomycin therapy, with weekly monitoring recommended for standard cases and more frequent monitoring for high-risk patients.

Rationale for CK Monitoring

• Daptomycin can cause myopathy, defined as muscle aching or muscle weakness with increases in CK values greater than 10 times the upper limit of normal (ULN) 1
• Rhabdomyolysis, with or without acute renal failure, has been reported with daptomycin use 1
• The Infectious Diseases Society of America recommends weekly CK monitoring for all patients on daptomycin therapy 2

Monitoring Schedule

• Standard monitoring: Check CK levels weekly for all patients on daptomycin 2, 1
• High-risk patients: More frequent monitoring (more than once weekly) is recommended for:
  • Patients with renal impairment 1, 3
  • Patients receiving concurrent HMG-CoA reductase inhibitors (statins) 2, 1
  • Patients receiving high-dose daptomycin (≥6 mg/kg/day) 2, 3

Risk Factors for CK Elevation

• Renal insufficiency significantly increases the risk of muscle toxicity 2, 3
• Higher doses of daptomycin (>6 mg/kg/day) are associated with greater risk of CK elevation 2, 4
• Concurrent statin therapy increases the risk of myopathy 2, 1
• More frequent dosing (more than once daily) increases risk of CK elevation 1

Management of CK Elevations

• Discontinue daptomycin in patients with unexplained signs and symptoms of myopathy with CK elevations >1,000 U/L (~5× ULN) 1
• In asymptomatic patients with marked CK elevations >2,000 U/L (≥10× ULN), discontinuation is also recommended 1
• Consider temporarily suspending statins in patients receiving daptomycin 1
• A novel approach for managing mild, asymptomatic CK increases is to withhold a single daptomycin dose and resume therapy 24 hours later, which may allow continuation of therapy without further CK elevations 5, 6

Clinical Pearls and Pitfalls

• Muscle pain can occur without pronounced CK elevation, so monitor for symptoms even when CK levels are only mildly elevated 7
• The median time to onset of CK elevation in patients with renal impairment is approximately 11.5 days, suggesting the need for more frequent monitoring than once weekly in these high-risk patients 3
• CK elevations typically resolve within one week of discontinuing daptomycin 6
• Patients should be monitored specifically for development of muscle pain or weakness, particularly in the distal extremities 1

By following these monitoring guidelines, you can identify daptomycin-associated myopathy early and intervene appropriately to prevent serious complications such as rhabdomyolysis.