Clinical pharmacokinetics during continuous ambulatory peritoneal dialysis

Direct Oral Anticoagulants in Patients With ESRD and Kidney Transplantation

Direct oral anticoagulant (DOAC) use has significantly increased because major medical organizations endorse their role for conditions in which anticoagulation is indicated. Owing to important pharmacokinetic properties, the use of apixaban and rivaroxaban requires careful consideration in at-risk populations such as those with kidney disease. Both apixaban and rivaroxaban undergo some degree of renal elimination, and thus total drug exposure is increased in patients with renal insufficiency and/or those undergoing renal replacement therapy (RRT). The available clinical trial and real-world data in this population suggests that apixaban is likely at least comparably effective as warfarin at preventing thromboembolic events and is likely safer when evaluating bleeding risk. Rivaroxaban data is more limited, and the reported results are more discordant. Both apixaban and rivaroxaban have been used successfully in patients with end-stage renal disease (ESRD) undergoing kidney transplant listing as well as in the posttransplant setting. Prospective clinical trials evaluating the safety and efficacy of apixaban and rivaroxaban in various conditions where anticoagulation is indicated should include patients with ESRD and kidney transplant recipients to help further define the role that these important novel agents should play in these complex patient populations.

Pharmacokinetics in Critically Ill Children with Acute Kidney Injury

Acute kidney injury (AKI) is a commonly encountered comorbidity in critically ill children. The coexistence of AKI disturbs drug pharmacokinetics and pharmacodynamics, leading to clinically significant consequences. This can complicate an already critical clinical scenario by causing potential underdosing or overdosing giving way to possible therapeutic failures and adverse reactions. Current available studies offer little guidance to help maneuver such complex dosing regimens and decision-making in pediatric patients as most of them are done on heterogeneous groups of adult populations. Though there are some studies on drug dosing during continuous renal replacement therapy (CRRT), their utility is in question because of the recent advances in CRRT technology. Our review aims to discuss the principles of pharmacokinetics pertinent for honing the existing practices of drug dosing in critically ill children with AKI, and the various complexities and intricate challenges involved. This in turn will provide a framework to help enable caretakers to tailor dosing regimens in complex clinical setups with further ease and precision.

Oral Hypoxia-Inducible Factor Prolyl Hydroxylase Inhibitor Roxadustat (FG-4592) for Treatment of Anemia in Chronic Kidney Disease: A Placebo-Controlled Study of Pharmacokinetic and Pharmacodynamic Profiles in Hemodialysis Patients

Roxadustat (FG‐4592), an oral hypoxia‐inducible factor prolyl hydroxylase inhibitor that stimulates erythropoiesis, was evaluated in a phase 1b study in patients with end‐stage renal disease with anemia on hemodialysis. Seventeen patients, on epoetin‐alfa maintenance therapy with stable hemoglobin levels ≥10 g/dL, had epoetin‐alfa discontinued on day 3 and were enrolled in this double‐blind placebo‐controlled study. Two cohorts were randomized 3:1 (roxadustat: placebo). Patients received single doses of roxadustat (1 or 2 mg/kg) or placebo 1 hour after hemodialysis on day 1 and 2 hours before dialysis on day 8. Maximum plasma concentration and area under the plasma concentration–time curve for patients receiving roxadustat were slightly more than dose proportional and elimination half‐life ranged from 14.7 to 19.4 hours. Roxadustat was highly protein bound (99%) in plasma, and dialysis contributed a small fraction of the total clearance: only 4.56% and 3.04% of roxadustat recovered from the 1 and 2 mg/kg dose groups, respectively. Roxadustat induced transient elevations of endogenous erythropoietin that peaked between 7 and 14 hours after dosing and returned to baseline by 48 hours after dosing. Peak median endogenous erythropoietin levels were 96 mIU/mL and 268 mIU/mL for the 1‐ and 2‐mg/kg doses, respectively, within physiologic range of endogenous erythropoietin responses to hypoxia at high altitude or after blood loss. No serious adverse events were reported, and there were no treatment‐ or dose‐related trends in adverse event incidence.

Drug dosing consideration in patients with acute and chronic kidney disease-a clinical update from Kidney Disease: Improving Global Outcomes (KDIGO)

Drug dosage adjustment for patients with acute or chronic kidney disease is an accepted standard of practice. The challenge is how to accurately estimate a patient's kidney function in both acute and chronic kidney disease and determine the influence of renal replacement therapies on drug disposition. Kidney Disease: Improving Global Outcomes (KDIGO) held a conference to investigate these issues and propose recommendations for practitioners, researchers, and those involved in the drug development and regulatory arenas. The conference attendees discussed the major challenges facing drug dosage adjustment for patients with kidney disease. In particular, although glomerular filtration rate is the metric used to guide dose adjustment, kidney disease does affect nonrenal clearances, and this is not adequately considered in most pharmacokinetic studies. There are also inadequate studies in patients receiving all forms of renal replacement therapy and in the pediatric population. The conference generated 37 recommendations for clinical practice, 32 recommendations for future research directions, and 24 recommendations for regulatory agencies (US Food and Drug Administration and European Medicines Agency) to enhance the quality of pharmacokinetic and pharmacodynamic information available to clinicians. The KDIGO Conference highlighted the gaps and focused on crafting paths to the future that will stimulate research and improve the global outcomes of patients with acute and chronic kidney disease.