Drug dosing considerations for the critically ill patient with liver disease

Citrate pharmacokinetics in critically ill liver failure patients receiving CRRT

Citrate has been proposed as anticoagulation of choice in continuous renal replacement therapy (CRRT). However, little is known about the pharmacokinetics (PK) and metabolism of citrate in liver failure patients who require CRRT with regional citrate anticoagulation (RCA). This prospective clinical PK study was conducted at King Chulalongkorn Memorial Hospital between July 2019 to April 2021, evaluating seven acute liver failure (ALF) and seven acute-on-chronic liver failure (ACLF) patients who received CRRT support utilizing RCA as an anticoagulant at a citrate dose of 3 mmol/L. For evaluation of the citrate PK, we delivered citrate for 120 min and then stopped for a further 120 min. Total body clearance of citrate was 152.5 ± 50.9 and 195.6 ± 174.3 mL/min in ALF and ACLF, respectively. The ionized calcium, ionized magnesium, and pH slightly decreased after starting citrate infusion and gradually increased to baseline after stopping citrate infusion. Two of the ACLF patients displayed citrate toxicity during citrate infusion, while, no ALF patient had citrate toxicity. In summary, citrate clearance was significantly decreased in critically ill ALF and ACLF patients receiving CRRT. Citrate use as an anticoagulation in these patients is of concern for the risk of citrate toxicity.

Pharmacokinetics and safety of revefenacin in subjects with impaired renal or hepatic function

Purpose

Revefenacin, a long-acting muscarinic antagonist for nebulization, has been shown to improve lung function in patients with chronic obstructive pulmonary disease. Here we report pharmacokinetic (PK) and safety results from two multicenter, open-label, single-dose trials evaluating revefenacin in subjects with severe renal impairment (NCT02578082) and moderate hepatic impairment (NCT02581592).

Subjects and methods

The renal impairment trial enrolled subjects with normal renal function and severe renal impairment (estimated glomerular filtration rate <30 mL/min/1.73 m²). The hepatic impairment trial enrolled subjects with normal hepatic function and moderate hepatic impairment (Child-Pugh class B). Subjects received a single 175-µg dose of revefenacin through nebulization. PK plasma samples and urine collections were obtained at multiple time points for 5 days following treatment; all subjects were monitored for adverse events.

Results

In the renal impairment study, the maximum observed plasma revefenacin concentration (C_max) was up to 2.3-fold higher and area under the concentration–time curve from time 0 to infinity (AUC_inf) was up to 2.4-fold higher in subjects with severe renal impairment compared with those with normal renal function. For THRX-195518, the major metabolite of revefenacin, the corresponding changes in C_max and AUC_inf were 1.8- and 2.7-fold higher, respectively. In the hepatic impairment study, revefenacin C_max and AUC_inf were 1.03- and 1.18-fold higher, respectively, in subjects with moderate hepatic impairment compared with those with normal hepatic function. The corresponding changes in THRX-195518 C_max and AUC_inf were 1.5- and 2.8-fold higher, respectively.

Conclusion

Systemic exposure to revefenacin increased modestly in subjects with severe renal impairment but was similar between subjects with moderate hepatic impairment and normal hepatic function. The increase in plasma exposure to THRX-195518 in subjects with severe renal or moderate hepatic impairment is unlikely to be of clinical consequence given its low antimuscarinic potency, low systemic levels after inhaled revefenacin administration, and favorable safety profile.

The Impact of Liver and Renal Dysfunction on the Pharmacokinetics and Pharmacodynamics of Sedative and Analgesic Drugs in Critically Ill Adult Patients

The use of sedative and analgesic drug therapy is often necessary for the care of critically ill patients. Renal and hepatic dysfunction, which occurs frequently in this patient population, can significantly alter drugs' pharmacokinetic and pharmacodynamics properties. By anticipating how these medications may be affected by liver or kidney dysfunction, health care practitioners may be able to provide tailored dosing regimens that ensure optimal comfort while minimizing the risk of adverse events.