Pharmacokinetic considerations of commonly administered antimicrobial agents in hematopoietic stem cell transplant patients

INTRODUCTION: Hematopoietic stem cell transplantation (HSCT) is considered the treatment of choice for various malignant and nonmalignant hematologic disorders. HSCT patients are commonly subject to polypharmacy and receive multiple therapeutic regimens during the pre-, peri-, and post-transplantation periods. Administration of various antimicrobial agents as prophylactic or therapeutic regimens is essential in HSCT patients. AREAS COVERED: This comprehensive review, focuses mainly on the pharmacokinetic (PK) aspects and therapeutic drug monitoring (TDM) of commonly administered antimicrobial agents including antibacterial, antiviral, and antifungal agents in HSCT patients. Additionally, alterations in PK parameters and specific recommendations for TDM are discussed in detail. EXPERT OPINION: Since HSCT patients often have altered PK characteristics and require multiple concomitant medications, individualized dosing based on their PK and pharmacogenetic profiles is crucial. Close monitoring of potential drug-drug interactions (PDDIs) and plasma concentrations are essential to achieve optimal clinical response, minimize drug-related toxicities, and improve post-transplant survival. In general, many of the commonly administered antibiotics in HSCT patients showed increased volume of distribution and clearance, decreased half-lives, and therefore decreased area under the curve (ACU) values compared to the normal population. Therefore, higher doses of these antibiotics should be administered along with close patient monitoring and assessment of plasma concentrations.