title: High lethality and minimal variation after acute self-poisoning with carbamate insecticides in Sri Lanka - implications for global suicide prevention.
abstract: BACKGROUND
  Highly hazardous organophosphorus (OP) insecticides are responsible for most pesticide poisoning deaths. As they are removed from agricultural practice, they are often replaced by carbamate insecticides of perceived lower toxicity. However, relatively little is known about poisoning with these insecticides.
  
  
  METHODS
  We prospectively studied 1288 patients self-poisoned with carbamate insecticides admitted to six Sri Lankan hospitals. Clinical outcomes were recorded for each patient and plasma carbamate concentration measured in a sample to confirm the carbamate ingested.
  
  
  RESULTS
  Patients had ingested 3% carbofuran powder (719), carbosulfan EC25 liquid (25% w/v, 389), or fenobucarb EC50 liquid (50% w/v, 127) formulations, carbamate insecticides of WHO Toxicity Classes Ib, II, and II, respectively. Intubation and ventilation was required for 183 (14.2%) patients while 71 (5.5%) died. Compared with carbofuran, poisoning with carbosulfan or fenobucarb was associated with significantly higher risk of death [carbofuran 2.2%; carbosulfan 11.1%, OR 5.5 (95% CI 3.0-9.8); fenobucarb 6.3%, OR 3.0 (1.2-7.1)] and intubation [carbofuran 6.1%; carbosulfan 27.0%, OR 5.7 (3.9-8.3); fenobucarb 18.9%, OR 3.6 (2.1-6.1)]. The clinical presentation and cause of death did not differ markedly between carbamates. Median time to death was similar: carbofuran 42.3 h (IQR 5.5-67.3), carbosulfan 21.3 h (11.5-71.3), and fenobucarb 25.3 h (17.3-72.1) (p = 0.99); no patients showed delayed onset of toxicity akin to the intermediate syndrome seen after OP insecticide poisoning. For survivors, median duration of intubation was 67.8 h (IQR 27.5-118.8) with no difference in duration between carbamates. Reduced GCS at presentation was associated with worse outcome although some patients with carbosulfan died after presentation with normal GCS.
  
  
  CONCLUSIONS
  We did not find carbamate insecticide self-poisoning to vary markedly according to the carbamate ingested although the case fatality varied according to the concentration and formulation of the insecticide. Carbamate poisoning did not appear to be much less toxic than poisoning with some liquid OP insecticide formulations, e.g., chlorpyrifos EC40, that we have previously noted in these same hospitals (Lancet 2005, 366:1452-1459; QJM 2006, 99:513-522). Replacement of WHO Class II Toxicity OP insecticides in agriculture with high-strength liquid carbamate formulations may not substantially reduce case fatality after pesticide poisoning and, therefore, global suicide rates.
authors.affiliation: a Department of Pharmacology , Toxicology, and Therapeutics, University/BHF Centre for Cardiovascular Science, University of Edinburgh , Edinburgh , UK ;
authors.forename: Thomas
authors.initials: T
authors.lastname: Lamb
authors.affiliation: a Department of Pharmacology , Toxicology, and Therapeutics, University/BHF Centre for Cardiovascular Science, University of Edinburgh , Edinburgh , UK ;
authors.forename: Liza R
authors.initials: LR
authors.lastname: Selvarajah
authors.affiliation: b South Asian Clinical Toxicology Research Collaboration, Department of Clinical Medicine , University of Peradeniya , Peradeniya , Sri Lanka ;|c Department of Pharmacology, School of Medical Sciences , University of Sydney , Sydney , Australia ;
authors.forename: Fahim
authors.initials: F
authors.lastname: Mohamed
authors.affiliation: b South Asian Clinical Toxicology Research Collaboration, Department of Clinical Medicine , University of Peradeniya , Peradeniya , Sri Lanka ;|d Department of Medicine , University of Kelaniya , Kelaniya , Sri Lanka ;
authors.forename: Shaluka
authors.initials: S
authors.lastname: Jayamanne
authors.affiliation: b South Asian Clinical Toxicology Research Collaboration, Department of Clinical Medicine , University of Peradeniya , Peradeniya , Sri Lanka ;
authors.forename: Indika
authors.initials: I
authors.lastname: Gawarammana
authors.affiliation: e Therapeutics Research Centre, School of Medicine , University of Queensland , Brisbane , Australia ;|f Department of Pharmaceutical Chemistry, Faculty of Pharmacy , Helwan University , Helwan , Egypt.
authors.forename: Ahmed
authors.initials: A
authors.lastname: Mostafa
authors.affiliation: b South Asian Clinical Toxicology Research Collaboration, Department of Clinical Medicine , University of Peradeniya , Peradeniya , Sri Lanka ;|c Department of Pharmacology, School of Medical Sciences , University of Sydney , Sydney , Australia ;
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Buckley
authors.affiliation: e Therapeutics Research Centre, School of Medicine , University of Queensland , Brisbane , Australia ;
authors.forename: Michael S
authors.initials: MS
authors.lastname: Roberts
authors.affiliation: a Department of Pharmacology , Toxicology, and Therapeutics, University/BHF Centre for Cardiovascular Science, University of Edinburgh , Edinburgh , UK ;|b South Asian Clinical Toxicology Research Collaboration, Department of Clinical Medicine , University of Peradeniya , Peradeniya , Sri Lanka ;
authors.forename: Michael
authors.initials: M
authors.lastname: Eddleston
mesh_terms: D000818:Animals; D002219:Carbamates / Q000097:blood / Q000737:chemistry / Q000506:poisoning*; D015331:Cohort Studies; D006801:Humans; D007306:Insecticides / Q000097:blood / Q000737:chemistry / Q000506:poisoning*; D007928:Lethal Dose 50; D015394:Molecular Structure; D009026:Mortality / Q000639:trends*; D011041:Poisoning / Q000097:blood / Q000401:mortality / Q000628:therapy; D011446:Prospective Studies; D013188:Sri Lanka / Q000453:epidemiology; D013405:Suicide / Q000706:statistics & numerical data; D016896:Treatment Outcome; D000092864:Suicide Prevention
chemical_list: D002219:Carbamates; D007306:Insecticides
keywords: Lung; pesticide poisoning; suicide