title: Topical lidocaine enhanced by laser pretreatment: a safe and effective method of analgesia for facial rejuvenation.
abstract: BACKGROUND
  Injectable forms of anesthesia for nonsurgical facial rejuvenation, although efficacious, are uncomfortable for the patient. Preclinical studies have demonstrated that laser pretreatment at low energies enhances absorption of topical lidocaine.
  
  
  OBJECTIVE
  The authors assess the safety and efficacy of laser-assisted transdermal delivery of topical anesthetic.
  
  
  METHODS
  Ten patients were split into 2 groups (A and B). All patients received 15 g of BLT (20% benzocaine, 6% lidocaine, and 4% tetracaine triple anesthetic cream) for 20 minutes with no occlusion. Then the cream was removed and the first blood draw taken. Group A patients were pretreated with the full ablative laser and group B patients with a fractional ablative laser to the full face. A further 15 g BLT was applied for another 20 minutes. Group A patients then underwent full ablative laser treatment, and group B received fractionated ablative laser treatment. Blood draws were taken at 60, 90, 120, 180, and 240 minutes after the initial topical anesthetic application, and the serum was analyzed for lidocaine and monoethylglycinexylidide (MEGX) levels. Patients were asked to rate the pain felt at intervals during the procedure.
  
  
  RESULTS
  No patient required supplemental nerve blocks. Pain scores were equivalent at the end of the first pass for both groups (P = .436). Group A patients had significantly lower pain scores at the start of the second laser treatment (P = .045), but pain scores became equivalent by the end (P = .323). Combined serum lidocaine and MEGX levels were significantly higher in group A patients up to 90 minutes (peak average of 0.61 µg/mL for group A and 0.533 µg/mL for group B; P = .0253), which corresponded to greater initial analgesic effect.
  
  
  CONCLUSIONS
  Data from this study demonstrate that topical anesthetic for facial rejuvenation can be enhanced with laser pretreatment while maintaining safe blood serum levels. Further studies should examine optimal application amount and time to allow safe multipass facial rejuvenation without the need for invasive nerve blocks.
authors.affiliation: Plastic Surgery Department, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
authors.forename: Georgette
authors.initials: G
authors.lastname: Oni
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Rasko
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Kenkel
mesh_terms: D000279:Administration, Cutaneous; D000698:Analgesia / Q000009:adverse effects / Q000379:methods*; D000704:Analysis of Variance; D019162:Anesthetics, Combined / Q000008:administration & dosage* / Q000009:adverse effects / Q000097:blood / Q000493:pharmacokinetics; D000779:Anesthetics, Local / Q000008:administration & dosage* / Q000009:adverse effects / Q000097:blood / Q000493:pharmacokinetics; D001566:Benzocaine / Q000008:administration & dosage; D001711:Biotransformation; D003357:Cosmetic Techniques / Q000009:adverse effects / Q000295:instrumentation; D004867:Equipment Design; D005157:Facial Pain / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control*; D006801:Humans; D053685:Laser Therapy / Q000009:adverse effects / Q000295:instrumentation; D054020:Lasers, Gas; D053844:Lasers, Solid-State; D008012:Lidocaine / Q000008:administration & dosage* / Q000009:adverse effects / Q000031:analogs & derivatives / Q000097:blood / Q000493:pharmacokinetics; D009824:Ointments; D010147:Pain Measurement; D012060:Rejuvenation; D012869:Skin Absorption; D015595:Skin Aging; D011795:Surveys and Questionnaires; D013748:Tetracaine / Q000008:administration & dosage; D013781:Texas; D016896:Treatment Outcome
chemical_list: D019162:Anesthetics, Combined; D000779:Anesthetics, Local; D009824:Ointments; D013748:Tetracaine; D008012:Lidocaine; C001173:monoethylglycinexylidide; D001566:Benzocaine
keywords: cosmetic medicine; laser-assisted transdermal delivery; pain; research; topical anesthetics