Pharmacokinetics of 400 mg ropivacaine after periarticular local infiltration analgesia for total knee arthroplasty

Abstract

Although great inter-individual variability was found between the maximum ropivacaine concentrations, both maximum total and unbound serum concentrations of ropivacaine remained well below the assumed systemic toxic thresholds of 4.3 and 0.56 μg/ml.

Pharmacokinetics of 400 mg Locally Infiltrated Ropivacaine After Total Knee Arthroplasty Without Perioperative Tourniquet Use

“…The anesthetic and surgical procedures have been described in a previous study conducted in our institution 11 and are identical except for the absence of a tourniquet during surgery. Briefly, all patients received standard multimodal analgesia with paracetamol 1000 mg 4 times a day, etoricoxib 90 mg once daily, and gabapentin twice daily (300/600 mg or 300/300 mg if >70 years old).…”

“…A baseline sample was taken immediately after placement of the sampling catheter; consecutive samples were obtained at T = 20, 40, 60, 90, 120, 240, 360, 480, 600, 720, and 1440 minutes by one of the investigators (S.M.K.B.). Based on the results of our previous study, 11 we added the 480-, 600-, and 720-minute samples to the sampling schedule.…”

“…11 Total ropivacaine concentrations were measured in all samples. The concentration of unbound ropivacaine of each patient was assessed in ultrafiltrate of the sample with the highest total ropivacaine concentration, as well as in those of the preceding and following time point samples.…”

“…In Table 3 and Figure 3, we have combined the results of the present study with those of our previous study. 11 …”

“…Nevertheless, worldwide, thousands of patients have received LIA for knee surgery with no apparent signs of systemic toxicity, and pharmacokinetic studies [9][10][11] have confirmed the safety of high doses of ropivacaine for LIA, with the concentration of unbound ropivacaine in plasma staying well below the toxic threshold.…”