Daptomycin pharmacokinetics in critically ill patients undergoing continuous renal replacement therapy

Interactions between mitochondrial dysfunction and other hallmarks of aging: Paving a path toward interventions that promote healthy old age

Current research on human aging has largely been guided by the milestone paper "hallmarks of aging," which were first proposed in the seminal 2013 paper by Lopez-Otin et al. Most studies have focused on one aging hallmark at a time, asking whether the underlying molecular perturbations are sufficient to drive the aging process and its associated phenotypes. More recently, researchers have begun to investigate whether aging phenotypes are driven by concurrent perturbations in molecular pathways linked to not one but to multiple hallmarks of aging and whether they present different patterns in organs and systems over time. Indeed, preliminary results suggest that more complex interactions between aging hallmarks must be considered and addressed, if we are to develop interventions that successfully promote healthy aging and/or delay aging-associated dysfunction and diseases. Here, we summarize some of the latest work and views on the interplay between hallmarks of aging, with a specific focus on mitochondrial dysfunction. Indeed, this represents a significant example of the complex crosstalk between hallmarks of aging and of the effects that an intervention targeted to a specific hallmark may have on the others. A better knowledge of these interconnections, of their cause-effect relationships, of their spatial and temporal sequence, will be very beneficial for the whole aging research field and for the identification of effective interventions in promoting healthy old age.

Population pharmacokinetics of daptomycin in adult patients undergoing continuous renal replacement therapy

Aim

The objective of this population pharmacokinetic (PK) analysis was to provide guidance for the dosing interval of daptomycin in patients undergoing continuous renal replacement therapy (CRRT).

Methods

A previously published population PK model for daptomycin was updated with data from patients undergoing continuous veno‐venous haemodialysis (CVVHD; n = 9) and continuous veno‐venous haemodiafiltration (CVVHDF; n = 8). Model‐based simulations were performed to compare the 24 h AUC, C_max and C_min of daptomycin following various dosing regimens (4, 6, 8, 10, and 12 mg kg⁻¹ every [Q] 24 h and Q48 h), with the safety and efficacy exposure references for Staphylococcus aureus bacteraemia/right‐sided infective endocarditis.

Results

The previously developed daptomycin structural population PK model could reasonably describe data from the patients on CRRT. The clearance in patients undergoing CVVHDF and CVVHD was estimated at 0.53 and 0.94 l h⁻¹, respectively, as compared with 0.75 l h⁻¹ in patients with creatinine clearance (CrCl) ≥ 30 ml min⁻¹. Daptomycin Q24 h dosing in patients undergoing CRRT resulted in optimal exposure for efficacy, with AUC comparable to that in patients with CrCl ≥ 30 ml min⁻¹. In contrast, Q48 h dosing was associated with considerably lower AUC_24–48h in all patients for doses up to 12 mg kg⁻¹ and is therefore inappropriate.

Conclusions

Q24 h dosing of daptomycin up to 12 mg kg⁻¹ provides comparable drug exposure in patients on CVVHD and in those with CrCl ≥ 30 ml min⁻¹. Daily daptomycin use up to 8 mg kg⁻¹ doses are appropriate for patients on CVVHDF, but higher doses may increase the risk of toxicity.

Pharmacokinetics of daily daptomycin in critically ill patients undergoing continuous renal replacement therapy

BACKGROUND

The optimal daptomycin dosing regimen for critically ill patients undergoing continuous renal replacement therapy (CRRT) has still to be established.

METHODS

Daptomycin pharmacokinetics was determined in 9 patients after administration of 6 mg/kg/day over 5 days.

RESULTS

At steady state, which was reached by day 3, the area under the curve over 24 h (AUC24h) was 667.4 ± 356.6 mg·h/l, and the maximum concentration (Cmax) was 66.9 ±25.3 mg/l. Mean CRRT clearance accounted for 48% (range 32-67%) of total clearance (mean 10.2 ml/min, range 6.1-18 ml/min). Significant correlations were observed between Cmax, minimum concentration (Cmin) and AUC24h (R(2) = 0.91, p < 0.001, and R(2) = 0.94, p < 0.001) and between albumin plasma concentration and free daptomycin (R(2) = 0.7, p = 0.009).

CONCLUSION

No significant accumulation occurred with a daily daptomycin dose of 6 mg/kg in patients undergoing CRRT with an effluent flow rate of >30 ml/kg/h. The quantification of trough concentrations (Cmin) appears to be a good surrogate to estimate AUC24h and to monitor daptomycin treatment in patients undergoing CRRT.

Vancomycin clearance in high-volume venovenous hemofiltration

OBJECTIVE

To report the pharmacokinetic and pharmacodynamic properties of vancomycin in 4 patients undergoing high-volume continuous venovenous hemofiltration (CVVH).

CASE SUMMARY

Data from 4 patients prescribed high-volume CVVH for acute renal failure treated with vancomycin were analyzed. Vancomycin plasma concentrations were measured 4 and 24 hours after the end of a 1-hour vancomycin infusion. The mean therapy fluid rate on initiation of vancomycin was 56.2 mL/kg/h (range 48.0-65.5). The mean loading dose of vancomycin was 18.3 mg/kg (range 14.7-19.7). Median vancomycin concentration 4 hours after the dose was 18.1 mg/L (range 13.1-30.0). At 24 hours after the dose, only 1 patient had a detectable vancomycin concentration (5.2 mg/L).

DISCUSSION

There was a large variability in the clearance of vancomycin in this patient population. Current strategies for dosing vancomycin may lead to subtherapeutic trough concentrations. Vancomycin dosing in this patient population should be based on a detailed assessment of the CVVH prescription, vancomycin concentrations, and clinical needs and response.

CONCLUSIONS

An initial vancomycin dose of 20-25 mg/kg with frequent monitoring and adjustment is recommended for patients receiving high-volume CVVH.

Experience with daptomycin daily dosing in ICU patients undergoing continuous renal replacement therapy

PURPOSE

For critically ill patients undergoing continuous renal replacement therapy (CRRT), daptomycin dosing recommendations are scarce. We, therefore, retrospectively assessed routinely measured daptomycin plasma concentrations, daptomycin dose administered and microbiological data in 11 critically ill patients with Gram-positive infections that had received daptomycin once daily.

METHODS

The retrospective analysis included critically ill patients treated at the intensive care unit (ICU) who had daptomycin plasma concentrations measured.

RESULTS

Daptomycin dose ranged from 3 to 8 mg/kg/q24 h in patients undergoing CRRT (n = 7) and 6 to 10 mg/kg/q24 h in patients without CRRT (n = 4). Peak and trough concentrations showed a high intra- and inter-patient variability in both groups, independent of the dosage per kg body weight. No drug accumulation was detected in CRRT patients with once-daily daptomycin dosing. Causative pathogens were Enterococcus faecium (n = 6), coagulase-negative Staphylococcus (n = 2), Staphylococcus aureus (n = 2) and unknown in one patient. Microbiological eradication was successful in 8 of 11 patients. Two of three patients with unsuccessful microbiological eradication and fatal outcome had an Enterococcus faecium infection.

CONCLUSION

In critically ill patients undergoing CRRT, daptomycin exposure with once-daily dosing was similar to ICU patients with normal renal function, but lower compared to healthy volunteers. Our data suggest that daptomycin once-daily dosing is appropriate in patients undergoing CRRT.