Cosmetic Surgery Times magazine, April 2001
Newer anesthetics found effective after 30-minute application.
By John Jesitus
Contributing Editor
— A comparative study of Topicaine, EMLA, and ELA-Max 5 showed Topicaine and ELA-Max 5 to be effective after a 30-minute application period.
Joshua P. Fogelman, M.D., who recently reported results of a study, said that 30
minutes after the anesthetics were removed, Topicaine and EMLA demonstrated
the highest efficacy.
Dr. Fogelman, whose efforts were assisted by Paul M. Friedman, M.D., Vicki
Levine, M.D., and Robin Ashinoff, M.D., is a chief resident at the NYU Medical
Center’s Department of Dermatology.
The study follows previous research by the same team which sought to gauge the
effectiveness of ELA-Max, EMLA, and two other topical anesthetics (tetracaine gel and betacaine-LA ointment) after a 60-minute application time. This research
showed ELA-Max and EMLA delivered superior performance both after the initial
application period and 30 minutes later.
“Because some physicians don’t want to have their patients wait in a waiting room or at home for 60 minutes before a procedure,” Dr. Fogelman said, “we decided this time to try an application period which may be more clinically relevant.”
Forearms tested
After randomly applying equal amounts of the anesthetics or a control to the volar forearms of 24 test subjects, the researchers assessed the degree of anesthesia achieved by applying a Q-switched Nd:YAG laser emitting energy at 1064 nm.
Similar testing was performed 15 and 30 minutes after removal of the Anesthetics, with patients’ responses being recorded on an ordinal scale of zero to four.
Immediately after 30 minutes of occlusion under a Tegaderm dressing, only EMLA’s
performance was not statistically superior to control. In contrast, Dr. Fogelman said Topicaine and ELA-Max 5 were quite statistically superior (p = 0.002). However, all three anesthetics were statistically superior
to control at 15 and 30 minutes after removal.
In comparing the anesthetics, researchers found both Topicaine and ELA-Max 5 statistically superior to EMLA immediately after removal, while Topicaine was the top performer 15 minutes after removal. At the 30-minute mark after removal of the anesthetics, Topicaine and EMLA outperformed ELA-Max 5.
“The other finding we noted was that Topicaine posted the lowest mean pain score at each time interval,” Dr. Fogelman stated,“but it was statistically significant only at the 15-minute interval.”
Side effects rare
As for the medications’ side effects, which included blanching or erythema at the site of application, these were very rare and tended to resolve themselves within two hours after anesthetics were removed.
Dr. Fogelman added: “One surprising conclusion was that ELA-Max 5 was not as
effective as Topicaine at 15 and 30 minutes
after removal.” In the previous study, ELAMax
(not ELA-Max 5) and EMLA were the
superior anesthetics. A possible explanation
for this is that occlusion is not recommended
for either ELA-Max or ELA-Max
5, though this was the methodology that
both studies employed.With that in mind,
Dr. Fogelman and his colleagues will begin
a study by year’s end to determine the
effect of occluded vs. nonoccluded application
methods.
Although the new study improves
upon its predecessor in that it was randomized
and included twice as many subjects,
it’s not immune to criticism.
As Dr. Fogelman pointed out: “A big
weakness in any anesthetic study performed
in this way is patients’ subjective
reporting of pain sensations,” which are
hard to quantify and therefore can make
comparing various products’ performance
levels difficult.
Another problem with studies like Dr.
Fogelman’s involves the differences in
pain scores noted. Just because one anesthetic
may fail to deliver statistically
superior performance at certain intervals,
that doesn’t mean it’s not providing
patients with adequate relief in a clinical
setting.
Accordingly, Dr. Fogelman determined
whether to use a product based solely on test
scores is for each physician to decide.
Dr. Fogelman has no financial interest
and received no financial support from the
manufacturers of the topical anesthetics or
laser used in the study. CST
Cosmetic Surgery Times magazine, April 2001 - Download/save this article, pdf file 380k
Comparative study of Topicaine, EMLA and ELA-MAX 5
Comparative study of three topical anesthetics:
Topicaine Gel, EMLA cream and ELA-Max 5 were compared in a double-blind, placebo controlled study in 24 human volunteers. The topical anesthetics were applied on four sites of the ante-arm of the patients, in randomly varying positions. The anesthetics were applied for 30 minutes, under occlusion. After the application time, a Nd-Yag laser was used to cause pain. Pain scores were assessed immediately post removal, fifteen minutes later and thirty minutes later.
Dr Paul A. Friedman, one of the investigators, presented the results of this study at the convention of the American Society of Lasers in Medicine and Surgery, in Reno, NV, in April 17, 2000.
(To obtain an original tape from the convention, contact: Professional Recording Services; 2501 22nd Ave North, Suite 1025.- St Petersburg; Florida 33713; and request: Tape L-15-0-III Dermatology/Plastic Surgery I/Friday Session; Cost of tape: $10)
The presentation was titled: "Comparative Study Of Three Topical Anesthetics After 30 Minutes Application Time"
The investigators were Dr Paul Friedman, Dr Joshua Fogelman, Dr Vicki Levine and Dr Robin Ashinoff, from the Department of Dermatology of New York University. They have no financial interest and received no financial support from the manufacturers of the three topical anesthetics or lasers used in this study.
At the previous year's meeting these investigators had reported the first prospective controlled study comparing the efficacy of several new topical anesthetics agents with laser induced pain stimuli. They had found that Ela-Max and EMLA were statistically superior to Eutectic-LA (known as Betacaine LA now) and tetracaine after 60 minutes of occlusion, and 30 minutes later. They also demonstrated that anesthetic efficacy improved 30 minutes after removal of each of the anesthetics.
Dr Friedman said, regarding the results of this new study: "At time zero, which represents immediately after the 30 minute application time, we found that TOPICAINE and Ela-Max 5 were statistically superior to control shown with the hashed marks, with a p-value of less than 0.002.
Fifteen minutes after removal of the anesthetics, they are all now statistically superior to control with a p-value of less than 0.005 and this trend continued, 30 minutes after removal.
Now, comparing individual anesthetics, we found that both Topicaine and Ela-Max 5 were statistically superior to EMLA after the 30-minute time point, with a p-value of less than 0.001.
Fifteen minutes after removal, Topicaine was the superior anesthetic alone, with a p-value of 0.001, while 30 minutes after the 30 minute application point, we found that both TOPICAINE and EMLA were statistically superior to Ela-Max 5.
Now if you follow the trend, you can see that both EMLA and TOPICAINE show statistically improved efficacy both 15 and 30 minutes after the removal, working from a reservoir of anesthetic that is stored in the stratum corneum, while Ela-Max 5 demonstrated a steady state of anesthesia.
We also performed a cost-comparison, and a 30 g tube of EMLA can be obtained from the NYU pharmacy for over $54, whereas Ela-Max 5 and TOPICAINE can be obtained through the manufacturers for less than half of that.
So in conclusion we found that TOPICAINE and Ela-Max 5 demonstrated effective anesthesia to laser-induced pain after only 30 minutes of occlusion, and that the highest level of anesthesia was obtained in our study with TOPICAINE and EMLA at 30 minutes after the 30 minute application time. Thank you."
