title: 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
  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/cm(2) for 532 nm and 5 J/cm(2) 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.
authors.affiliation: Department of Dermatology, Huangpu Hospital of The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, PR China. luodq@mail.sysu.edu.cn
authors.forename: Di-Qing
authors.initials: DQ
authors.lastname: Luo
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
mesh_terms: D000287:Administration, Topical; D000293:Adolescent; D000328:Adult; D000368:Aged; D000779:Anesthetics, Local / Q000008:administration & dosage*; D005260:Female; D005782:Gels; D006801:Humans; D053844:Lasers, Solid-State / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000188:drug therapy; D010859:Pigmentation Disorders / Q000601:surgery*; D013748:Tetracaine / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D000779:Anesthetics, Local; D005782:Gels; D013748:Tetracaine