A Comparison of Topical Application of 1% Tetracaine Gel Before and After the Procedure in Removal of Cutaneous Pigmentation with Q-Switched Neodymium-Doped Yttrium Aluminium Garnet Laser (1064/532 nm)

Abstract

Objective: To evaluate the anesthetic efficacy of topical application of 1% tetracaine gel before and after a Q-switched neodymium-doped yttrium aluminium garnet (Nd:YAG) laser procedure. Background Data: A variety of topical anesthetics are available for painful cutaneous procedures, including laser treatments, which are applied before treatment. Methods: Seventy-nine adults were assigned to Q-switched laser treatment at a wavelength of 532 nm (freckle, chloasma, and seborrheic keratosis) and 1064 nm (nevus fusco-caeruleus zygomaticus, nevus of Ota). Based on application time of tetracaine, there were three groups receiving each wavelength: 5 minutes before treatment, and 10 minutes before treatment, and after the procedure. Patients' lesions were divided into tetracaine-treated area and margin, which were treated with the same laser dose and wavelength. The energy density was 2 J/cm² for 532 nm and 5 J/cm² for 1064 nm. The pain relief score (PRS) for all groups, the latency time, and the time to maximal anesthesia of tetracaine for the after-procedure group were recorded. The PRSs were rated on visual analog scales. Results: The mean PRSs ± standard deviation of the group receiving the tetracaine 10 minutes before the procedure (42.37 ± 9.18) were higher than the scores of those receiving it 5 minutes before (26.32 ± 5.49)with the 532-nm laser. Using the gel after the procedure and using the 1064-nm and 532-nm lasers, the latency time was 20 to 80 seconds, the duration to maximal anesthesia was 2 to 6 minutes, and the maximum PRSs were 70 to 100, higher than the scores of those receiving tetracaine 10 minutes before the procedure (P < 0.001). The gel was well tolerated. Conclusions: Topical application of 1% tetracaine gel provides better anesthesia used 10 minutes before Q-switched Nd:YAG laser treatment than 5 minutes before but provides superior anesthesia and shorter latency time when applied after the procedure.