title: Aqueous humor lidocaine concentrations in topical and intracameral anesthesia.
abstract: OBJECTIVE
  To assess aqueous humor lidocaine concentrations in 2 common regimens of topical anesthesia and after intracameral injection of the anesthetic agent.
  
  
  METHODS
  University hospital eye clinic.
  
  
  METHODS
  Twenty patients having routine cataract surgery were randomized into 3 groups: 1 given 3 drops of lidocaine 4% before surgery; 1 given 6 drops; 1 given 3 drops plus an intracameral injection of 0.1 mL lidocaine 1%. Lidocaine concentration was measured in aqueous humor samples taken before surgery.
  
  
  RESULTS
  With 3 drops, aqueous lidocaine concentration was 1.4 micrograms/mL +/- 0.5 (SD) and with 6 drops, 4.3 +/- 1.5 micrograms/mL (P = .0015). With an intracameral injection, it was 341.8 +/- 152.6 micrograms/mL.
  
  
  CONCLUSIONS
  Measurable amounts of lidocaine entered the anterior chamber in topical anesthesia, and more entered when more drops were given. It is likely that concentrations in this range could anesthetize the iris, but they are far lower than concentrations after an intracameral injection.
authors.affiliation: Department of Ophthalmology, Umeå University Hospital, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Behndig
authors.forename: C
authors.initials: C
authors.lastname: Lindén
mesh_terms: D000287:Administration, Topical; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000772:Anesthesia, Local / Q000379:methods*; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000867:Anterior Chamber / Q000187:drug effects / Q000378:metabolism; D001082:Aqueous Humor / Q000378:metabolism*; D002387:Cataract Extraction; D002849:Chromatography, Gas; D006801:Humans; D007267:Injections; D008012:Lidocaine / Q000008:administration & dosage / Q000493:pharmacokinetics*; D008875:Middle Aged
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine