title: Activated charcoal decreases the risk of QT prolongation after citalopram overdose.
abstract: OBJECTIVE
  We determine whether single-dose activated charcoal (SDAC) administration after citalopram overdose reduces the proportion of patients developing abnormal QT prolongation.
  
  
  METHODS
  Data were collected retrospectively for citalopram overdose patients presenting to 8 emergency departments. Demographics, dose, coingested drugs, SDAC administration, and serial ECGs were extracted from medical records. The primary outcome was the proportion of patients who had an observed QT,RR combination at any time above an abnormal threshold, established as a predictor of torsade de pointes. We compared the proportion of patients with QT prolongation who received or did not receive SDAC. These data were analyzed within a Bayesian framework, using probabilities of abnormal QT,RR combinations with and without derived from a previous single-center study. WinBUGS was used to generate posterior estimates and credible intervals of the relative risk by combining the prior probabilities and the study data.
  
  
  RESULTS
  SDAC was administered on average 2.1 hours (range, 0.5 to 6.25 hours) after ingestion in 48 of 254 admissions, and abnormal QT,RR combinations occurred in 2 cases (4.2%), compared with 23 of 206 (11.2%) cases not receiving SDAC. There did not appear to be any clinically important difference in age, sex, dose, and cardiotoxic coingestants between the 2 groups. No cases of torsade de pointes occurred. The estimated relative risk of having an abnormal QT,RR combination for SDAC compared to no SDAC was 0.28 (0.06 to 0.70) (median with 2.5% and 97.5% credible limits). The probability that the relative risk was less than 1.0 was 0.99, which can be interpreted as very strong evidence in favor of a beneficial effect of SDAC. The absolute risk difference was estimated as 7.5% and the median number needed to treat as 13.3.
  
  
  CONCLUSIONS
  SDAC may be effective in reducing the risk of a prolonged QT in patients after citalopram overdose. Current trends toward nonuse of activated charcoal should be evaluated to determine whether patients poisoned by specific agents may benefit from activated charcoal administration.
authors: Menzies School of Health Research, Charles Darwin University, Darwin, Australia. Geoffrey.isbister@menzies.edu.au
authors: Geoffrey K
authors: GK
authors: Isbister
authors: Lena E
authors: LE
authors: Friberg
authors: Barrie
authors: B
authors: Stokes
authors: Nicholas A
authors: NA
authors: Buckley
authors: Christopher
authors: C
authors: Lee
authors: Naren
authors: N
authors: Gunja
authors: Simon G
authors: SG
authors: Brown
authors: Ellen
authors: E
authors: MacDonald
authors: Andis
authors: A
authors: Graudins
authors: Anna
authors: A
authors: Holdgate
authors: Stephen B
authors: SB
authors: Duffull
mesh_terms: D000328:Adult; D002606:Charcoal / Q000627:therapeutic use*; D015283:Citalopram / Q000009:adverse effects*; D016208:Databases, Factual; D062787:Drug Overdose / Q000188:drug therapy; D005260:Female; D006801:Humans; D008133:Long QT Syndrome / Q000139:chemically induced / Q000517:prevention & control*; D008297:Male; D015337:Multicenter Studies as Topic; D012189:Retrospective Studies; D017367:Selective Serotonin Reuptake Inhibitors / Q000009:adverse effects*
chemical_list: D002606:Charcoal; D015283:Citalopram; D017367:Selective Serotonin Reuptake Inhibitors