Background Linezolid is a new antimicrobial agent with a broad spectrum of activity against all clinically important gram positive bacteria, including methicillin resistant Staphylococcus aureus (MRSA) and vancomycin resistant enterococci (VRE). The incidence of linezolid induced thrombocytopenia was reported to be 2.4% in phase III trials. Clearance of linezolid is not altered in patents with renal insufficiency and no dose adjustment is necessary. Therefore, linezolid is a suitable and reasonable drug of choice for patients with renal insufficiency who have MRSA or VRE infection. Moreover, renal insufficiency is also known to cause thrombocytopenia.

Purpose This study investigated if the incidence of linezolid induced thrombocytopenia in a patient with renal insufficiency was higher than that of others with normal renal function.

Material and methods The case report was in relation to severe thrombocytopenia (platelet count <100 × 10⁹ platelets/L) in a patient with haemodialysis who was treated with linezolid for VRE infection. Then, a retrospective study was performed in patients treated with linezolid and to evaluate the incidence of linezolid induced thrombocytopenia.

Results 16 patients (10 females), with mean age of 64.8 years, were studied between August 2014 and August 2015. The samples size was small because of the limitations of using linezolid imposed by the national healthy insurance of Taiwan. 6 patients had decreased platelet count of >25% from baseline during treatment with linezolid and 4 (67%) had renal insufficiency (creatinine clearance <50 mL/min). Two patients with renal insufficiency had severe thrombocytopenia.

Conclusion The results showed that the incidence of linezolid induced thrombocytopenia was higher in patients with renal insufficiency. Clinicians should consider the potential risks of linezolid treatment and monitor closely platelet count in during linezolid treatment. Further studies should be encouraged to determine if dose adjustment of linezolid in renal insufficiency is necessary to reduce the incidence of linezolid related thrombocytopenia.

References and/or Acknowledgements

1. Clin Infect Dis 2006;42:66-72

2. Int J Antimicrob Agents 2008;28:345-51

3. Int J Antimicrob Agents 2014;44:242-7

4. Eur J Clin Pharmacol 2014;70:23-8

5. J Infect Chemother 2011;17:382-7

References and/or AcknowledgementsThis study was financially supported by the Department of Pharmacy, Kaohsiung Municipal Hsiao-Kang Hospital.

No conflict of interest.