TLC

Background: Edmond Laser Institute initiated a study of various formulations of previously tested ingredients in a
quest for a cream or ointment applicable to the skin that would give reasonably fast onset yet long enough duration of
action to give patients protection from the pain of laser treatments of varicose veins in the face or leg.

Twenty formulations were tested initially scheduled for 25 patients to be tested under each formulation. As
formulations were found to be notably less effective in pain control that formulations dropped from the study.

Results: The two formulations that produced satisfactory anesthesia of the skin contained the same carrier and
absorbent ingredients in the same ratios. They differed in that the active ingredient in one was tetracaine 4% while the
other contained tetracaine 4% plus lidocaine 2.5%. It was found that the difference in the level of anesthesia and the
onset and duration of effective anesthesia was not significantly approximately 30% of patients tested with tetracaine
4% sample experienced a noticeable edema associated with the expected erytherma over the area of application. This
was attributed to vascular hyperdilitation. This was seen in only 1.5% of patients treated with tetracaine 4%/lidocaine
2.5% sample. This difference is edema was also accompanied by lesser erytherma. This decrease was attributed too
less vascular dilatation. This decrease in vascular dilatation was felt to be a function of competing biphasic patterns of
vascular response between lidocaine and tetracaine (i.e. 1st phase vasoconstrictive - 2nd phase vasodilatation) the
second phase is an indication of anesthesia onset with the tetracaine lidocaine combination. This competition between
phases of onset between lidocaine and tetracaine effectively mutes the vasodilatation without decreasing the
anesthetic effect. This is advantageous to laser ablation especially when using green light laser.

Complications: Our clinical data charted by patient treatment includes use of a total of 1440/30gm tubes over a 3-year
period. This equates to over 3000 treatment applications of 10% of total body surface (slightly greater than 1/2 the total
skin surface of one leg). This encompasses over 1000 patients treated (avg. of 3 treatments per patient) 4 skin reactions
with blister formation were noted no long-term complications were noted. No systemic effects were detected in any of
the patients.

13,696/30 gm. tubes of this formulation have been used by other physicians in the United States with no reports of
either local or systemic complications.

Henry J. Pearce, M.D., F.A.C.S

Edmond Laser Institute