LET Anesthesia

1. See Also
   1. Local Skin Anesthesia
   2. Digital Block
   3. Lidocaine Local Skin Anesthesia (Xylocaine)
   4. EMLA cream
2. Indication: Skin Laceration Repair
   1. Topical anesthetic prior to local injection
   2. Replaces Tetracaine-Adrenaline-Cocaine (TAC)
   3. Safe down to age 2 years
3. Use
   1. Apply 1-3 ml to Laceration with cotton swab
   2. Secure remainder of dose using gauze
      1. Tape for 20-30 minutes
   3. Do not exceed 4 mg/kg of Lidocaine (up to 280 mg)
      1. Lidocaine 4% is 40 mg/ml (7 ml = 280 mg)
4. Recipe
   1. Ingredients
      1. Lidocaine HCL USP 4000 mg
      2. Epinephrine Bitartrate (55% Epinephrine) USP 180 mg
      3. Tetracaine HCl USP 500 mg
      4. Sodium Metabisulfite 75 mg
         1. Improves stability of Epinephrine
      5. Sterile Water for Irrigation qs add 100 ml
   2. Final concentrations
      1. Lidocaine 4%
      2. Epinephrine 0.1% or 1:1000
      3. Tetracaine 0.5%
   3. Preparation
      1. Place powdered ingredients in graduated cylinder
      2. Add to sterile water to reach 100 ml total
      3. Sterilize through 0.2 u filter
   4. Storage
      1. Store in a light resistant container
      2. Stability
         1. Lasts 6 months refrigerated
         2. Lasts 4 weeks at room Temperature
         3. Discard if solution discolors (should be clear)
   5. Gel preparation (better near mucous membranes)
      1. Start with 3 ml of LET solution (See above)
      2. Add 150 mg Methylcellulose 4000 cps
      3. Stir for 2-3 minutes
      4. Use immediately
   6. Suppliers
      1. Galliput, Inc. St Paul, MN, (800) 423-6967
      2. Hawkins Pharmaceutical Group
         1. http://www.HawkinsPharmaceutical.com
5. Efficacy
   1. Effective alternative to TAC
6. Advantages over TAC
   1. Less potential for toxicity
   2. Not a controlled substance
   3. Less expensive than TAC
7. References
   1. Kundu (2002) Am Fam Physician 66(1):99-102 [PubMed]
   2. Schilling (1995) Ann Emerg Med 25(2):203-8 [PubMed]