Can Daptomycin Cause Thrombocytopenia?
Yes, daptomycin can cause thrombocytopenia, though it is uncommon and occurs in less than 1% of patients according to FDA labeling. 1
Evidence from FDA Drug Labeling
The FDA-approved prescribing information explicitly lists thrombocytopenia as a recognized adverse reaction to daptomycin:
- Thrombocytopenia is documented as occurring in <1% of adult patients receiving daptomycin in complicated skin and soft tissue infection trials 1
- The FDA label categorizes thrombocytopenia under blood/lymphatic system adverse reactions that are "possibly or probably drug-related" 1
- Other hematologic effects listed include leukocytosis, thrombocytosis, eosinophilia, and increased INR 1
Clinical Case Evidence
Published case reports confirm daptomycin-induced thrombocytopenia as a real clinical entity:
- The first documented case of daptomycin-induced immune thrombocytopenia involved a patient with severe thrombocytopenia where serum antibodies bound to platelets in the presence of daptomycin on flow cytometry, resulting in fatal cerebral hemorrhage 2
- A case of simultaneous thrombocytopenia and neutropaenia occurred with prolonged daptomycin use for culture-negative endocarditis 3
Comparative Risk Assessment
When comparing daptomycin to linezolid for VRE bloodstream infections:
- No significant difference in thrombocytopenia rates was found between daptomycin (10.6%) and linezolid (12.1%) (RR 0.85; 95% CI 0.68-1.05; p=0.13) 4
- This suggests daptomycin carries lower or equivalent thrombocytopenia risk compared to linezolid, which is well-known for causing severe thrombocytopenia 4
Clinical Implications and Monitoring
While thrombocytopenia is rare with daptomycin, clinicians should:
- Monitor complete blood counts during prolonged therapy, particularly beyond 2 weeks of treatment 3
- Consider daptomycin-induced thrombocytopenia in the differential diagnosis when platelet counts drop during therapy 2
- Recognize that immune-mediated mechanisms may be involved, though antibody testing is not routinely available 2
- Discontinue daptomycin promptly if drug-induced thrombocytopenia is suspected, as platelet counts typically recover after cessation 3, 2
Important Caveats
The primary monitoring focus with daptomycin should remain on CPK elevation and myopathy, which are far more common adverse effects requiring weekly monitoring, especially at doses ≥6 mg/kg/day 5, 1. Thrombocytopenia, while documented, represents a much rarer complication that does not require routine specific monitoring beyond standard clinical assessment.