Hematologic effects of linezolid in young children.
BACKGROUND
Linezolid is an effective and well-tolerated antibiotic for the treatment of Gram-positive infections, including hospital and community-acquired pneumonia and complicated and uncomplicated skin and skin structure infections. In adults linezolid treatment for >/=2 weeks has been associated with reversible hematopoietic suppression, primarily thrombocytopenia.


OBJECTIVE
To evaluate the occurrence of hematologic effects in children with Gram-positive infections in an open label study of linezolid vs. vancomycin.


METHODS
Detailed analyses of hematologic data, including reported hematologic adverse events, complete blood counts, reticulocyte index (RI) and iron studies (serum iron and transferrin saturation), were conducted in both groups at baseline and during and after treatment with the use of an intent-to-treat analysis.


RESULTS
Three hundred sixteen patients (median age, 1.65 yr) randomized 2:1 to linezolid (n = 215) or vancomycin (n = 101) were treated. Total treatment durations were similar in the vancomycin group (12.2 +/- 6.4 days; median, 11.0 days) and the linezolid group (11.3 +/- 5.0 days; median, 11.0 days) (P = 0.20). No significant differences were noted in drug-related hematologic events, such as thrombocytopenia (linezolid, 1.9% vs. vancomycin, 0%; P = 0.170), anemia (linezolid, 1.4% vs. vancomycin, 1.0%; P = 0.771) or neutropenia (linezolid, 0% vs. vancomycin, 0%). Hemoglobin values also were similar between treatment groups when assessed by shifts from baseline to lowest recorded value. Frequency of occurrence of any substantially abnormal value for hemoglobin (15.7% vs. 12.4%), platelets (12.9% vs. 13.4%) and neutrophils (5.9% vs. 4.3%) were similar in the linezolid and vancomycin groups. No clinically relevant changes in RI or iron studies were noted between treatment groups, and parallel increases in RI occurred with both linezolid and vancomycin.


CONCLUSIONS
No significant differences in hematologic profiles between linezolid and vancomycin occurred in this pediatric population.
Meissner
H Cody
HC
Pediatric Infectious Diseases, New England Medical Center, Tufts University School of Medicine, 750 Washington Street, NEMCH Box 321, Boston, MA 02111, USA. CMeissner@tufts-nemc.org
Townsend
Timothy
T
Wenman
Wanda
W
Kaplan
Sheldon L
SL
Morfin
Maria Rayo
MR
Edge-Padbury
Barbara
B
Naberhuis-Stehouwer
Sharon
S
Bruss
Jon B
JB
D000081:Acetamides / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology; D000284:Administration, Oral; D000367:Age Factors; D000740:Anemia / Q000139:chemically induced*; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology; D000890:Anti-Infective Agents / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology; D002648:Child; D002675:Child, Preschool; D005260:Female; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007262:Infusions, Intravenous; D000069349:Linezolid; D008297:Male; D009503:Neutropenia / Q000139:chemically induced*; D023303:Oxazolidinones / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology; D013921:Thrombocytopenia / Q000139:chemically induced*; D014640:Vancomycin / Q000008:administration & dosage / Q000009:adverse effects* / Q000494:pharmacology
D000081:Acetamides; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D006454:Hemoglobins; D023303:Oxazolidinones; D014640:Vancomycin; D000069349:Linezolid