Topical lidocaine and injected lidocaine penetrate different depths of the skin layers
the verdict
INSUFFICIENT LEANING
refutedsupported
the weight of evidence
3 sources for · 0 against
The available literature discusses the penetration depths of transdermal or topical lidocaine and mentions comparative anesthesia testing, but does not provide comprehensive direct evidence establishing that topical and injected lidocaine penetrate distinct skin layers.
Determination of lidocaine concentrations in skin after transdermal iontophoresis: effects of vasoactive drugs. The purpose of this study was to investigate the effect of vasoactive drugs on transdermal lidocaine inotophoresis by measuring the concentrations of radiolabeled lidocaine which has penetrated the skin. Previous studies had demonstrated that coinotophoresis of vasoactive drugs could modulate the transcutaneous flux of lidocaine and suggested that a dermal depot of lidocaine was involved. To address this, lidocaine hydrochloride (14C) was iontophoresed in vivo in anesthetized weanling pigs either alone or with the vasodilator tolazoline or the vasoconstrictor norepinephrine. Tissue cores under the active electrode were then collected, quick-frozen, and sectioned on a cryostat, and then the radioactivity was determined in each 40-microns section. Coiontophoresis with norepinephrine resulted in increased concentrations of lidocaine in skin up to a depth of 3 mm. These concentrations decreased to lidocaine-alone levels after a 4-hr washout. Tolazoline decreased tissue concentrations of lidocaine. Concentrations were intermediate when lidocaine alone was administered.
Lidocaine anesthesia: comparison of iontophoresis, injection, and swabbing
## Abstract
The duration and depth of anesthesia produced by lidocaine with three methods of administration were studied. To test duration of anesthesia, either lidocaine or placebo was administered by iontophoresis, subcutaneous infiltration, or swabbing to each of three sites 3 cm apart on the flexor surface of each forearm of 27 subjects. To test for feeling, the tip of a 21-gauge hypodermic needle was pressed on each application site every five minutes until feeling returned. The depth of anesthesia achieved with iontophoresis or infiltration of lidocaine was tested on the flexor surface of each forearm of 12 subjects, with a random assignment of application methods to each arm. Lidocaine iontophoresis produced local anesthesia of significantly longer duration (p less than 0.001) than topical application of lidocaine or placebo by any route of administration, but of significatnly shorter duration (p less tahn 0.001) than lidocaine infiltration. The results showed that lidocaine iontophoresis is an effective method of producing local anesthesia for about five minutes without requiring the use of a hypod
Evaluation of the penetration depth of transdermally applied 3% GA MHPh 2Na-10% lidocaine gel in man | Journal of Anesthesia
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# Evaluation of the penetration depth of transdermally applied 3% GA MHPh 2Na-10% lidocaine gel in man
* Original Articles
* Published:January 1993
* Volume 7, pages 21–26, (1993)
* [Cite this article](#citeas)
[Journal of Anesthesia](https://link.springer.com/journal/540)[Aims and scope](https://link.springer.com/journal/540/aims-and-scope)[Submit manuscript](https://www.editorialmanager.com/joan)
* [Tatsuhiko Kano](#auth-Tatsuhiko-Kano-Aff1)[1](#Aff1),
* [Mari Nakamura](#auth-Mari-Nakamura-Aff2)[2](#Aff2),
* [Akira Hashiguchi](#auth-Akira-Hashiguchi-Aff1)[1](#Aff1),
* [Kazuyuki Masuda](#auth-Kazuyuki-Masuda-Aff2)[2](#Aff2),
* [Tohru Morioka](#auth-Tohr
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