cefamandole and cefazedone

Topics: Cefaclor; Cefadroxil; Cefamandole; Cefazolin; Cefmetazole; Cefonicid; Cefoperazone; Cefotaxime; Cefotiam; Cefsulodin; Ceftizoxime; Cephalexin; Cephalosporins; Cephamycins; Cephradine; Humans; Intestinal Absorption; Kinetics; Moxalactam; Tissue Distribution

Cephalosporin antibiotics cause a variety of hematologic disturbances in man, the pathogeneses and hematopathology of which remain poorly characterized. There is a need for a well-defined animal model in which these blood dyscrasias can be studied. In four subacute toxicity studies, the intravenous administration of cefonicid or cefazedone to beagle dogs caused a dose-dependent incidence of anemia, neutropenia, and thrombocytopenia after 1-3 months of treatment. A nonregenerative anemia was the most compromising of the cytopenias and occurred in approximately 50% of dogs receiving 400-500 mg/kg cefonicid or 540-840 mg/kg cefazedone. All three cytopenias were completely reversible following cessation of treatment; the time required for recovery of the erythron (approximately 1 month) was considerably longer than that of the granulocytes and platelets (hours to a few days). Upon rechallenge with either cephalosporin, the hematologic syndrome was reproduced in most dogs tested; cefonicid (but not cefazedone)-treated dogs showed a substantially reduced induction period (15 +/- 5 days) compared to that of the first exposure to the drug (61 +/- 24 days). This observation, along with the rapid rate of decline in red cell mass parameters of affected dogs, suggests that a hemolytic component complicated the red cell production problem and that multiple toxicologic mechanisms contributed to the cytopenia. We conclude that the administration of high doses of cefonicid or cefazedone to dogs can induce hematotoxicity similar to the cephalosporin-induced blood dyscrasias described in man and thus provides a useful model for studying the mechanisms of these disorders.

Topics: Anemia; Animals; Cefamandole; Cefazolin; Cefonicid; Cephalosporins; Disease Models, Animal; Dogs; Dose-Response Relationship, Drug; Female; Hematologic Diseases; Male; Neutropenia; Thrombocytopenia

Cephalosporin treatment in man has been associated with blood dyscrasias that include a time- and dose-related anemia, neutropenia, and thrombocytopenia, the hematopathology of which remains poorly characterized. A similar hematologic syndrome can be produced in dogs following daily intravenous injections of 540-840 mg/kg cefazedone or 400-500 mg/kg cefonicid for 1-3 months. Using this animal model, histologic and cytologic changes in blood, bone marrow, spleen, and liver were studied over the course of the cephalosporin-induced cytopenias. Peripheral blood cytologic observations included an absence, generally, of erythroid regenerative changes, increased numbers of macroplatelets, spherocytosis, erythroblastemia, and toxic neutrophil morphology. Interim and postmortem cytologic and histologic observations of bone marrow included hypoplastic and toxic changes, primarily in cytopenic dogs receiving high doses of cefonicid, and regenerative changes in hematopoietic tissue of affected cefazedone-treated animals. The latter included variable erythroid hyperplasia, increased megakaryocytes, and decreased marrow fat and was accompanied by evidence of extra-medullary hematopoiesis and increased hemosiderin and hemophagocytosis in liver and splenic tissue. The incidence and severity of these changes were dose-dependent, corresponded with the cytopenias observed peripherally, and, like the cytopenias, were fully reversible. These observations suggest that the hematologic syndrome associated with cephalosporin treatment in the dog has multiple toxicologic mechanisms, which include peripheral cytotoxic effects and bone marrow damage with depressed or ineffective hematopoiesis.

Topics: Animals; Bone Marrow; Cefamandole; Cefazolin; Cefonicid; Cephalosporins; Disease Models, Animal; Dogs; Hematopoiesis; Liver; Neutrophils; Paraproteinemias