title: [Methaemoglobinaemia after using EMLA cream].
abstract: BACKGROUND
  The use of creams is considered to be generally safe. However, systemic side effects can occur.
  
  
  METHODS
  A 22-year-old woman came to the emergency department with dyspnea, confusion and 'blue' skin after laser treatment of the upper legs for excessive hair. She had used three tubes of a eutectic mixture of local anaesthetics (EMLA) cream containing lidocaine/prilocaine for analgesia. Her oxygen saturation was 87%, measured with pulse oximetry. Blood gas analysis showed a concentration of oxy-Hb of 79% and a met-Hb of 19%. Our working diagnosis was methaemoglobinaemia as a result of using excessive amounts of EMLA cream. Because the met-Hb concentration decreased spontaneously and the oxy-Hb concentration consequently normalised, we did not administer methylene blue. The patient was discharged symptom-free after several hours of observation.
  
  
  CONCLUSIONS
  An overdose of EMLA cream, whether or not in combination with laser-induced skin damage, can produce a high systemic o-toluidine concentration. This can lead to methaemoglobinaemia. In such cases, the pulse oximeter is not reliable for measuring the oxygen saturation; therefore, blood gas analysis is necessary for making a diagnosis.
authors.affiliation: Sint Lucas Andreas Ziekenhuis, afd. Interne geneeskunde, Amsterdam, the Netherlands. j.selder@slaz.nl
authors.forename: Jasper  L
authors.initials: J
authors.lastname: Selder
authors.forename: Jan
authors.initials: J
authors.lastname: Veenstra
mesh_terms: D000700:Analgesics / Q000009:adverse effects / Q000627:therapeutic use; D019162:Anesthetics, Combined / Q000008:administration & dosage / Q000009:adverse effects*; D000779:Anesthetics, Local / Q000009:adverse effects; D001784:Blood Gas Analysis; D005260:Female; D006801:Humans; D008012:Lidocaine / Q000008:administration & dosage / Q000009:adverse effects*; D000077442:Lidocaine, Prilocaine Drug Combination; D008708:Methemoglobinemia / Q000139:chemically induced* / Q000175:diagnosis; D010146:Pain / Q000188:drug therapy; D011318:Prilocaine / Q000008:administration & dosage / Q000009:adverse effects*; D055815:Young Adult
chemical_list: D000700:Analgesics; D019162:Anesthetics, Combined; D000779:Anesthetics, Local; D000077442:Lidocaine, Prilocaine Drug Combination; D011318:Prilocaine; D008012:Lidocaine