Pharmacokinetics of Lidocaine Delivered: RESULTS

In: Anesthesia

9 Dec 2009

Lidocaine Delivered

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After removal of the patch, the site of application was examined to evaluate the area for signs of irritation. No tissue discoloration, swelling, or sloughing was noted in association with patch application in any of the patients. In addition, no drug-related adverse effects were associated with patch application. None of the patients experienced any complications, as defined by accepted hospital criteria, during the general anesthetic procedure or during the dental treatment.

Lidocaine and MEGX Plasma Concentrations

Values were obtained for the amount of lidocaine in venous blood samples from each of the patients at various time intervals after a 5-minute patch application. None of the subjects had measurable plasma lidocaine levels at baseline. The mean peak plasma lidocaine concentration was 82 ± 26 ng/mL, ranging from 41 to 128 ng/mL. The mean time at which peak plasma lidocaine concentration was attained was 9 ± 1 minutes, ranging from 1 to 15 minutes. Figure 2 displays the mean plasma lidocaine concentrations as a function of time. A measurable mean concentration of 41 ng/mL was observed at the first time point, only 1 minute after patch removal. The mean concentration increased at the 5-minute time point to 59 ng/mL. The mean concentration then reached 64 ng/mL at 10 minutes and remained relatively constant at 62 ng/mL after 15 minutes. This was followed by a substantial reduction to 27 ng/mL at 45 minutes. canada viagra online

Figure 2. Mean plasma lidocaine concentrations

Figure 2. Mean plasma lidocaine concentrations at various time points. Error bars denote standard deviations.

The concentration of MEGX in the venous blood samples was also obtained for each of the patients at various time intervals, and the mean maximum values were calculated. None of the subjects had measurable plasma MEGX levels at baseline. The mean maximum plasma MEGX concentration was 11.98 ± 1.44 ng/mL, ranging from 5.4 to 18.98 ng/mL. All subjects demonstrated a maximum MEGX level at the latest time point, 45 minutes. Figure 3 displays the steady increase in the mean plasma MEGX concentrations from the earliest time point up to 45 minutes after removal of the patch. As a function of time, no detectable MEGX concentrations were measured for any subject 1 minute after patch removal. However, mean values reached 1.95 ng/mL at 5 minutes and then increased to 3.83 ng/mL at 10 minutes and again to 5.71 ng/mL at 15 minutes. This was followed by a maximum concentration of 11.98 ng/mL at 45 minutes.

Figure 3. Mean plasma monoethylglycinexylidide

Figure 3. Mean plasma monoethylglycinexylidide concentrations at various time points. Error bars denote standard deviations.


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