ClassMechanism of action/toxicitySigns and symptomsTreatment
Organophosphates
  • Acephate (Orthene)

  • Chlorphoxim (Baythion-C)

  • Chlorpyrifos (Dursban, Lorsban)

  • Diazinon

  • Dimethoate (Cygon, DeFend)

  • Ethoprop (Mocap)

  • Fenitrothion (Sumithion)

  • Fenthion (Baytex)

  • Malathion (Cythion)

  • Naled (Dibrome)

  • Terbufos (Counter)

Inhibit cholinesterase leading to excess acetylcholineCNS—anxiety, seizures, Skeletal nerve-muscle junctions, autonomic ganglia—twitching, tachycardia, muscle weakness (nicotinic effects); peripheral cholinergic neuroeffector unctions— “all faucets on”— sweating, salivation, diarrhea, tearing (muscarinic effects); miosis (pinpoint pupils) most commonly, but 15 percent have mydriasis secondary to epinephrine release from adrenals due to nicotinic receptor stimulation.
  1. Draw red cell cholinesterase and plasma pseudocholinesterase levels before therapy. Do not delay treatment while awaiting results.

  2. Maintain and protect airway.

  3. Supplemental oxygen

  4. Atropine (preservative-free, if possible), 2 to 5 mg IV every 15 minutes (adults and children >12 years) until pulmonary symptoms controlled; children < 12 years, 0.05 to 0.1 mg/kg every 15 minutes; doses repeated as needed for symptom control (up to 24 hours, taper dose)

  5. Pralidoxime (2-PAM, Protopam) IV, 1 to 2 g (adults) over 10 minutes, 20 to 50 mg/kg (<12 years) over 30 minutes; repeated in 1 to 2 hours and at 10- to 12-hour intervals as needed for symptom control; alternatively: continuous IV infusion 10 to 20 mg/kg/hr (up to 500 mg/hr) after initial bolus and continued for 24 hours

  6. Furosemide (Lasix), 40 to 160 mg IV for pulmonary congestion remaining after full atropinization

  7. Benzodiazepine for seizures (diazepam [Valium]), 5 to 10 mg slow IV push, repeated every 5 to 10 minutes to control or maximum 30 mg in adults; 0.2 to 0.5 mg/kg IV every 5 minutes to maximum of 10 mg in children >5 years, 5 mg in children <5 years; lorazepam may also be used

Carbamates
  • Carbaryl (Sevin)

  • Pirimicarb (Aphox, Rapid)

  • Propoxur (Baygon)

  • Timethacarb (Landrin)

  • Other carbamates

Reversible Cholinesterase Inhibition (carbamoyl-acetylcholinesterase [AChE] complex Dissociates much more easily and quickly than OP-AChE complex)Cholinergic crisis with “all faucets on”; CNS depression with coma, seizures, hypotonicity in serious toxic exposures
  1. Maintain and protect airway.

  2. Optimize oxygenation/supplemental oxygen.

  3. Atropine IV (preferably or IM) Adults, children >12 years, 2.0 to 4.0 mg every 15 minutes until secretions controlled; children <12 years, 0.05 to 0.10 mg/kg every 15 minutes until secretions controlled; continue 2 to 12 hours; continued signs of poisoning indicate need for more atropine.

  4. Furosemide (Lasix), 40 to 160 mg, if basilar rales persist after atropinization

  5. Pralidoxime not indicated in pure carbamate poisoning; may be necessary in mixed organophosphate/carbamate poisoning or unknown poisoning with cholinergic syndrome.

Organochlorines
  • Chlorobenzilate

  • Dicofol (Kelthane)

  • Dienochlor (Pentac)

  • Endosulfan

  • Lindane (Kwell)

Induction of hyperexcitable state in central and peripheral nervous system by disruption of normal flow of sodium and potassium across the axon membrane; may antagonize GABA-mediated inhibition in CNSSeizures, headache, dizziness, nausea, vomiting, paresthesias, incoordination, tremor/twitching following topical treatment for lice/scabies or accidental or intentional ingestion of liquid pesticide
  1. Maintain and protect airway.

  2. Ensure adequate oxygenation.

  3. Seizure control with diazepam; adults, 5 to 10 mg IV push over 2 to 5 minutes, repeated every 10 minutes as necessary; children, <12 years 0.04 to 0.2 mg/kg every 10 minutes, monitoring airway closely; lorazepam may be used as an alternative.

  4. IV fluids with dextrose (5 to 10 percent) and thiamine 100 to 500 ng/L

  5. Dysrhythmias from rare myocardial irritant effect treated with lidocaine (1 mg/kg bolus, 2 to 4 mg/minute continuous infusion)

Biocides
Pyrethrins/pyrethroids
  • Allethrin

  • Cyfluthrin (Baythroid)

  • Cypermethrin (Barricade, Cymbush, Cynoff, Demon)

  • Deltamethrin

  • Dimethrin

  • Fenothrin

  • Fenvalerate

  • Permethrin (Ambush, Dragnet, Nix, Pounce)

  • Remethrin

Pyrethrins are derived from chrysanthemums; pyrethroids are synthetic compounds with longer half-lives; both can produce toxic effects on the nervous system but are not well absorbed and are effectively and quickly detoxified by mammalian liver enzyme systems.The most severe symptoms are seizures, though highly uncommon unless highly exposed (usually through ingestion of large quantities); tremor, incoordination, salivation, vomiting; topical exposure can produce short-term paresthesias, especially of the hands and face; a small portion of the population (1 to 3 percent) is allergic to pyrethrins/pyrethroids—resulting in symptoms ranging from nasal stuffiness to asthma.
  1. Skin decontamination by thorough washing with soap and water is suggested; vitamin E oil preparations are effective in preventing and treating paresthesias; corn oil and petrolatum are less effective.

  2. Seizures controlled with benzodiazepines.

  3. Standard antiallergy therapy for hypersensitivity reactions.

Bacillus thuringiensis
  • Variety aizawai (Agree, Mattch)

  • Variety israelensis (Aquabac, Skeetal)

  • Variety kurstaki (Bactur, Dipel)

Wide range of products derived from several varieties of this organism; highly limited effects on mammalian systemsMild irritative pulmonary symptoms in some involved in manufacturing process, not in mixers or appliers; theoretical risk of respiratory infection in immunocompromised individuals; single corneal ulceration reported, successfully treated with standard antibiotics; mild gastroenteritis with heavy ingestion
  1. Symptomatic treatment following decontamination

Repellants
Diethyltoluamide—DEET (Muskol, Off!, Skeeter Beater, Skeeter Cheater, Skintastic for Kids, others)
Mechanism of toxicity unknownCNS depression followed by seizures; rare unless applied excessively under occlusion; mild skin irritating effects with repeated use; corneal and mucosal irritation; nausea and vomiting with ingestion and, rarely, hypotension, tachycardia with heavy dermal exposure
  1. Decontamination

  2. Control of seizures with benzodiazepines

  3. Supportive care