Can Ertapenem Cause Thrombocytosis?
Yes, ertapenem can cause thrombocytosis, though this is an infrequent adverse effect. This hematologic complication has been documented in case reports and is listed in the FDA drug label, though it occurs rarely in clinical practice.
Evidence from FDA Drug Label
The FDA-approved prescribing information for ertapenem explicitly lists platelet count increased as a drug-related laboratory adverse experience, occurring in 2.8% of adult patients treated in clinical trials 1. This represents laboratory monitoring data from controlled studies where platelet elevations were systematically tracked 1.
Case Report Evidence
Two published case reports provide direct evidence of ertapenem-induced thrombocytosis:
A 2024 case report documented acute thrombocytosis in a 62-year-old female treated with ertapenem for complicated urinary tract infection caused by E. coli, where discontinuation of ertapenem normalized the platelet count 2.
A 2017 case report described thrombocytosis in a 68-year-old female receiving ertapenem for complicated abdominal infection, emphasizing the importance of considering drug side effects when evaluating thrombocytosis 3.
Clinical Context and Mechanism
Beta-lactam antibiotics as a class have been associated with thrombocytosis, though the data are difficult to interpret due to the possibility of acute-phase reactions in infected patients being the actual cause 4. The mechanism may involve thrombocyte-stimulating properties similar to other medications known to cause platelet elevations 4.
Clinical Implications
Physicians should monitor platelet counts in patients receiving ertapenem, particularly if thrombocytosis develops during therapy 2, 3.
Consider ertapenem as a potential cause when evaluating new-onset thrombocytosis in patients receiving this antibiotic, after excluding other common causes such as infection, inflammation, malignancy, or iron deficiency 2, 3.
Discontinuation of ertapenem should be considered if thrombocytosis is clinically significant or symptomatic, as platelet counts normalize after drug cessation 2.
Important Caveat
While thrombocytosis is documented, it remains an infrequent adverse effect compared to the more common side effects of ertapenem such as diarrhea, nausea, and infusion site reactions 1. The clinical significance of drug-induced thrombocytosis must be weighed against the therapeutic benefit of ertapenem for serious infections requiring carbapenem therapy.