title: Heated lidocaine/tetracaine patch (Synera, Rapydan) compared with lidocaine/prilocaine cream (EMLA) for topical anaesthesia before vascular access.
abstract: BACKGROUND
  We compared the lidocaine/tetracaine patch [Synera (USA), Rapydan (Europe)], a novel heat-aided patch using a eutectic mixture of lidocaine 70 mg and tetracaine 70 mg, with a eutectic mixture of lidocaine 25 mg ml(-1) and prilocaine 25 mg ml(-1) (EMLA Cream). The agents were administered at different time periods for local topical anaesthesia before a vascular access procedure.
  
  
  METHODS
  In this double-blind, paired study, 82 adult volunteers were randomized to receive the lidocaine/tetracaine patch on one anticubital surface and lidocaine/prilocaine cream on the other concurrently for 10, 20, 30, or 60 min before a vascular access procedure. Subjects rated pain intensity using a 100 mm visual analogue scale (VAS). Skin reactions and adverse events were also evaluated.
  
  
  RESULTS
  Median VAS scores were significantly lower for the lidocaine/tetracaine patch than for lidocaine/prilocaine cream in the 10 min (P=0.010), 20 min (P=0.042), and 30 min (P=0.001) application groups. The lidocaine/tetracaine patch was associated with significantly more erythema than lidocaine/prilocaine cream at 20, 30, and 60 min, whereas lidocaine/prilocaine cream produced more blanching than the lidocaine/tetracaine patch at 30 and 60 min. Two subjects reported nausea and faintness associated with the vascular access procedure; one was withdrawn from the study.
  
  
  CONCLUSIONS
  The lidocaine/tetracaine patch provided effective anaesthesia with an application time as short as 10 min and was better than lidocaine/prilocaine cream at all application times shorter than 60 min, demonstrating a substantial improvement in time to onset of anaesthesia. The lidocaine/tetracaine patch provided an important alternative to lidocaine/prilocaine cream for topical local anaesthesia.
authors.affiliation: Prism Ideas Ltd, Regent House Princes Court, Beam Heath Way, Nantwich, Chesire CW5 7PQ, UK. james.sawyer@prismideas.com
authors.forename: J
authors.initials: J
authors.lastname: Sawyer
authors.forename: S
authors.initials: S
authors.lastname: Febbraro
authors.forename: S
authors.initials: S
authors.lastname: Masud
authors.forename: M A
authors.initials: MA
authors.lastname: Ashburn
authors.forename: J C
authors.initials: JC
authors.lastname: Campbell
mesh_terms: D000279:Administration, Cutaneous; D000293:Adolescent; D000328:Adult; D000772:Anesthesia, Local / Q000379:methods; D019162:Anesthetics, Combined / Q000008:administration & dosage; D000779:Anesthetics, Local / Q000008:administration & dosage*; D004311:Double-Blind Method; D004338:Drug Combinations; D016503:Drug Delivery Systems; D005260:Female; D006358:Hot Temperature; D006801:Humans; D008012:Lidocaine / Q000008:administration & dosage*; D000077442:Lidocaine, Prilocaine Drug Combination; D008297:Male; D008875:Middle Aged; D009824:Ointments; D010146:Pain / Q000209:etiology / Q000517:prevention & control; D010147:Pain Measurement / Q000379:methods; D018962:Phlebotomy / Q000009:adverse effects*; D011318:Prilocaine / Q000008:administration & dosage*; D013748:Tetracaine / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D019162:Anesthetics, Combined; D000779:Anesthetics, Local; D004338:Drug Combinations; D000077442:Lidocaine, Prilocaine Drug Combination; D009824:Ointments; D011318:Prilocaine; D013748:Tetracaine; D008012:Lidocaine