Phenobarbital-associated bone marrow aplasia: a case report and review of the literature

Evolving Role of Pharmacogenetic Biomarkers to Predict Drug-Induced Hematological Disorders

ABSTRACT

Drug-induced hematological disorders constitute up to 30% of all blood dyscrasias seen in the clinic. Hematologic toxicity from drugs may range from life-threatening marrow aplasia, agranulocytosis, hemolysis, thrombosis to mild leukopenia, and thrombocytopenia. Pathophysiologic mechanisms underlying these disorders vary from an extension of the pharmacological effect of the drug to idiosyncratic and immune-mediated reactions. Predicting these reactions is often difficult, and this makes clinical decision-making challenging. Evidence supporting the role of pharmacogenomics in the management of these disorders in clinical practice is rapidly evolving. Despite the Clinical Pharmacology Implementation Consortium and Pharmacogenomics Knowledge Base recommendations, few tests have been incorporated into routine practice. This review aims to provide a comprehensive summary of the various drugs which are implicated for the hematological adverse events, their underlying mechanisms, and the current evidence and practical recommendations to incorporate pharmacogenomic testing in clinical care for predicting these disorders.

Meropenem-induced pancytopenia in a preterm neonate: a case report

BACKGROUND

A post-marketing surveillance study has reported an association between meropenem use and the incidence of hematologic abnormalities, including leukopenia, thrombocytopenia, hemolysis, and neutropenia, but the precise incidence in neonates is unknown. Here, we report meropenem-induced pancytopenia in a preterm neonate.

CASE PRESENTATION

A preterm newborn Pakistani received intravenous meropenem 40 mg/kg every 8 hours to treat Klebsiella pneumoniae in blood cultures and suspected meningitis. The baby developed severe thrombocytopenia, with a platelet count of 22 × 103 cells/mm3, low hemoglobin level of 9.7 g/dl, and low absolute neutrophil count (ANC) of 816 cells/mm3 on days 3, 14, and 17 of meropenem therapy, respectively. Based on the blood culture and institutional guidelines, meropenem treatment was continued with monitoring and supportive care for a total of 19 days. After discontinuation of meropenem, the baby was monitored continuously for hematological changes, and low counts persisted for 3 days. ANC improved to > 1500 cells/mm3 on the fourth day, and the platelet count reached > 150 × 103 cells/mm3 for the first time on the seventh day of meropenem discontinuation. All subsequent complete blood count (CBC) reports showed improving trends. The baby was discharged on the 48th day of life (DOL), with follow-up monitoring of CBC. The baby was kept on iron supplements, and hemoglobin level of 11.2 g/dl was observed on the 59th DOL.

CONCLUSION

Neonatal pancytopenia may lead to serious health complications; therefore, clinicians and pharmacists need to vigilantly monitor CBC in this vulnerable population, even when administering meropenem in septic doses for the recommended duration.

Anticonvulsant drugs and hematological disease

Many antiepileptic drugs (AEDs) are associated with hematological disorders that range from mild thrombocytopenia or neutropenia to anemia, red cell aplasia, until bone marrow failure. Fortunately, potentially fatal hematological disorders such as aplastic anemia are very rare. This review investigates hematological effects associated with classic and newer AEDs: a PubMed search indexed for MEDLINE was undertaken to identify studies in adults, children and animals using the name of all anticonvulsant drugs combined with the terms "hematological disease" and "hematological abnormalities" as key words. The most common hematological alterations occur with older AEDs than newer. Indeed, careful hematological monitoring is needed especially using carbamazepine, phenytoin and valproic acid. The pathogenetic mechanisms are still unknown: they seem to be related to an immunological mechanism, but drugs pharmacokinetics and pharmacodynamics interactions may also play an important role. Further research is needed to assess the real pathogenetic mechanism at the basis of hematological complications caused by AEDs.