Can meropenem (antibiotic) cause thrombocytosis (elevated platelet count)?

Meropenem and Thrombocytosis: Association and Clinical Implications

Meropenem can cause thrombocytosis (elevated platelet count) as a documented adverse effect, particularly in patients with renal impairment, though clinical bleeding related to this elevation has not been reported in the literature.

Evidence for Meropenem-Induced Thrombocytosis

The FDA drug label for meropenem specifically mentions thrombocytosis as an adverse laboratory change:

• The drug label states that "increased platelets" is among the hematologic changes that can occur with meropenem use 1
• In patients with renal impairment, thrombocytopenia (not thrombocytosis) has been observed, but no clinical bleeding has been reported 1
• A comprehensive safety review of meropenem in nearly 5,000 patients identified thrombocytosis as one of the most commonly reported meropenem-related laboratory adverse events, occurring in 1.6% of patients 2

Mechanism and Clinical Significance

The mechanism by which meropenem causes thrombocytosis is not fully elucidated, but beta-lactam antibiotics as a class have been associated with thrombocytosis. However, this association is complicated by the possibility that the thrombocytosis may be due to an acute-phase reaction in infected patients rather than a direct drug effect 3.

The clinical significance of meropenem-induced thrombocytosis appears to be limited:

• No clinical bleeding events have been reported in association with meropenem-induced thrombocytosis 1
• Secondary (reactive) thrombocytosis rarely causes bleeding complications 4

Management Considerations

When thrombocytosis is observed in a patient receiving meropenem:

1. Confirm true thrombocytosis (not pseudothrombocytosis) and check platelet function if clinically indicated 4

2. Monitor platelet counts until normalization, typically within 3-4 weeks 4

3. Continue standard thromboprophylaxis as indicated for the patient's condition 4

4. No specific treatment is required for secondary thrombocytosis related to meropenem 4

5. Distinguish between primary and secondary thrombocytosis to guide treatment decisions:

   • Secondary thrombocytosis (like that caused by meropenem) is usually self-limiting
   • Primary thrombocytosis is a clonal myeloproliferative neoplasm requiring different management 4

Important Caveats

• Meropenem has also been associated with thrombocytopenia (decreased platelets) in some cases, particularly in patients with renal impairment 1
• A pediatric case report has documented meropenem-induced thrombocytopenia associated with hypersensitivity reaction 5
• Avoid overtreatment of secondary thrombocytosis with antiplatelet agents or cytoreductive therapy 4

Monitoring Recommendations

• For patients on meropenem who develop thrombocytosis, regular monitoring of platelet counts is recommended until normalization
• If platelet counts exceed 400,000/mm³, consider evaluating for other causes of thrombocytosis
• In patients with renal impairment receiving meropenem, more frequent monitoring of platelet counts may be warranted 1

Overall, while meropenem can cause thrombocytosis, this adverse effect appears to be transient and rarely of clinical significance in most patients.