Pesticides, Herbicides, Fungicides and Insecticides


  • Sources
    • Rodenticide/insecticide and depilatories
    • Barium sulfate (contrast)
  • Effects/MOA
    • Causes hypokalemia due to redistribution – inh Ca-activated K rectifier channels → QT prolong
  • Clinical Manifestations
    • Paralysis
    • Severe hypoK within 2 hours
    • Parkinsonism findings on MRI
  • MGMT/Notes
    • White powder that resembles FLOUR
    • Pulmonary 
    • ORAL sodium sulfate or Mg sulfate (not IV- converts to barium sulfate=bad)
    • HD

Methyl bromide

  • Effects/MOA
    • Oral and dermal routes 
    • Direct cytotoxic (intact methyl bromide) and alkylating agent
    • BUT
    • Neuro effects occur without antecedent irritant effects
    • Greenhouse workers at risk
  • Clinical Manifestations
    • Neuro sx (cns depression) followed by agitation, seizure, coma, death
    • Convulsions, rapid CV collapse (ARDS leading to CV collapse is most common cause of death)
  • MGMT/Notes
    • BAL+NAC
    • HD for bromide
    • DECON!/PPE! – adheres to rubber, leather
    • OSHA PEL (permissible exposure limit)
    • 3x heavier than air
    • Metabolized to formaldehyde and methanethiol (neuro and visual changes)


  • Sources
    • Chlorinated hydrocarbon
  • Effects/MOA
    • Inhalation is the primary exposure route
  • Clinical Manifestations
    • Similar to CCl4 and chloroform (liver) met in the liver by 2E1 to electrophilic products
    • Similar to CCl4/APAP, liver tox (but also independent renal tox can occur)
  • MGMT/Notes
    • OSHA TWA TEL (time-weighted average, toxic exposure limit)
    • Extremely volatile – easy to be exposed (lung primary inj site) – normally in soybean oil (prevents volatilization)

Metal phosphides and Phosphine

  • Effects/MOA
    • Aluminum phosphide, Zinc/Mg/Ca phosphide – release phosphine gas(PH3) when exposed to atmospheric moisture (faster when exposed to HCl)
    • Met Acid w gap common
    • Providers should don PPE/N95
    • PH3 exposure as a byproduct of Meth production using RED Phosphorus (white phosphorus=phossy jaw, hypocalcemia, hyperkalemia)
    • Can be absorbed transdermal but low and rare
  • Clinical Manifestations
    • PH3- protoplasmic toxin, inhibits cytochrome c-oxidase (also decreases mitochondrial complexes I, II, IV and V)
    • PH3 is corrosive – mucous membrane burns/alveoli (ARDS)
    • Irritation to Shock, cv collapse
    • AlP – pts will have high jugular venous pressure
  • MGMT/Notes
    • DECON
      • N95 mask does NOT protect against PH3
    • IV NAC using PO apap regimen + IM vitamin E
    • Consider MgSO4 IV
    • Vegetable oil decon (orally) but limited due to risk of aspirating hydrocarbon/oil? Or hyperinsulinemia 
    • Maybe High dose insulin for AlP
    • KMnO4 (Potassium permanganate) or Boron added to GI decon NOT recommended 
    • No AC
    • AlP has greenish-grey color, garlicky odor. 3g tablet = 1g PH3, Ammonia and CO2
    • ZnP – rotten fish, quadrilateral crystalloid tablet
    • NIOSH (IDLH 50 ppm) – 
    • Blood testing not helpful – PH3 rapidly hydrolyzed

White phosphorus

  • Effects/MOA
    • Reacts with oxygen to form phosphous pentoxide → reacts with water to produce EXOTHERMIC reaction and phosphoric acid (corrosive)
  • Clinical manifestations
    • 3 Phase tox
      1. Vomiting/ hematemesis, hypotension, death
      2. Transient resolution
      3. Hepatic injury
  • MGMT/Notes
    • Exothermic, acid-producing, dehydrating reactions
    • Hepatic zone 1 necrosis -> fatty infiltrates within 6 hours
    • Vomitus can be luminescent and/or smoking and can spontaneously combust -> keep it and clothing under water
    • Can use copper sulfate ONCE (0.5%-1% solution)-> contaminated areas turn BLACK (copper phosphide). Similarly diluted silver nitrate can be alternative
    • IV NAC for liver
    • 1mg/kg lethal
    • Absorbed in skin/inhalation/GI (co-ingestants with fat, EtOH, liquids increase toxicity)

Sulfuryl fluoride

  • Effects/MOA
    • Measurable fluoride concentrations after exposure – fluorosis (look at Ca, Mg)
  • Clinical Manifestations
    • Respiratory, CNS and CV are primary targets
  • MGMT/Notes
    • Used for termites (Ca, Fl, Wa)
    • TLV-TWA (threshold limit value, time-weighted average)


  • Effects/MOA
    • Methemoglobinemia due to dichlorophenyhydroxylamine oxidizing Fe2+ to Fe3+
    • But not just MetHg since fatalities occur with levels <40% (usually requires >50-70% for death)
    • Pesticide exposure with intoxication and metheoglobinemia
  • Clinical manifestations
    • Mild, nonspecific findings to seizure coma death.
  • MGMT/Notes
    • Rhabdo is a feature
    • Numerous toxic metabolites via CYP450
    • Can cause sedation due to hydrocarbon (intoxication+methemoglobin=propanil)
    • Euglycemia! Adequate glucose needed to detoxify methemoglobin
    • AC reasonable
    • Methylene blue
    • Alternatives: NAC, cimetidine (used for dapsone), ascorbic acid


  • Effects/MOA
    • Induces redox cycling: Paraquat oxidized to paraquat radical (intracellular) then reduced by diaphorase + NADPH back to paraquat + superoxide radical
    • When NADPH+Oxygen run out, cell death → nonspecific cell necrosis
    • Cortinarius orellanus mushrooms contain biprydil like compound similar to paraquat (primarily known for nephrotoxicity due to orellanine)
  • Clinical Manifestations
    • Lung and Kidney common organs affected
    • Topical exposures- painful (ulceration -> desquamation)
    • Seizures with Diquat
  • Hemoperfusion/HD
    • AC/NAC/VitC/Cyclophosphamide/Xuebijing
    • SIPP (Severity Index of Paraquat Poisoning)
      • Paraquat level x hours since ingestion
        • SIPP < 10 = survival
        • SIPP 10-50 = death by lung fibrosis
        • SIP > 50 = death
    • Rate of increase in Scr predicts prognosis
      • < 0.3 mg/dL/hr over 5 hours = survival
      • > 0.5 mg/dL/hr over 12 hours = death
    • Poorly bioavailable, but F of 5% sufficient to cause death. As little as 10mL of 20% solution = death.
    • Can penetrate skin
    • Rapid distribution to all tissues, then redistribution to plasma.
    • Not metabolized almost fully renally eliminated
    • Diquat = pulmonary fibrosis in survivors
    • Urinary dithionite= Paraquat blue, diquat green
      • If light blue or negative @ 24 hours, good prognosis. Repeat in 6 hours to see if color change occurs.
    • Jones, Proudfoot and Scherrerman-Proudfoot


  • Effects/MOA
    • Structurally similar to glutamate
  • Clinical Manifestations
    • Interferes with glutamine synthase leading to hyperammonemia
    • Seizures
    • Metabolic acidosis
  • MGMT/Notes
    • Surfactants may contribute more to toxicity than glufosinate


  • Effects/MOA
    • May disrupt cell membrane and cause uncoupling of ox phos
  • MGMT/Notes
    • WHO U classification – unlikely to cause harm

Phenoxy compounds

2,4-D, 2,4,5-T; MCPA, MCPP, Mecoprop; Ioxynil, Bromoxynil

  • Effects/MOA
    • Uncoupling ox phos
    • Inhibits voltage-gated chloride channel-1 (ClC-1) – muscle and renal tissue
    • Disrupts blood-brain barrier AND neuronal membrane transport mechanisms
  • Clinical Manifestations
    • Corrosive – causes direct injury to GI
    • Ox phos uncoupler
    • Myotonia (ClC-1 inh)
    • Organophosphate like effects
  • MGMT/Notes
    • Alkalinize urine/HD, HP
    • Good PO absorption, poor dermal/inhal absorption
    • Extensively bound to albumin
    • T1/2 of 2,4-D is 20-30 hours
    • Non-linear kinetics – dose-dependent changes in absorption/protein binding, clearance
    • As pH decreases, toxicity increases
    • Can initially have tachypnea w resp alkalosis

Triazine compounds

  • Effects/MOA
    • Uncoupling ox phos
  • Clinical manifestations
    • Ox phos uncoupled
  • MGMT/Notes
    • Supportive care


  • Uses/source
    • Wood preservative
  • Clinical manifestations
    • Uncoupling ox phos
  • MGMT/Notes
    • Can use LIPID (log D ~ 3)
    • Manufacturing leads to production of dioxins


  • Uses/Source
    • Rubber/wood preservative
  • Clinical Manifestations
    • Inhibits uroporphyrinogen decarboxylase activity leading to accumulation of uroporphyrin and the induction of aminoleuvulinic acid synthase (Lead causes inc in delta-ala and protoporphyrin 9)
    • Porphyria cutanea tarda (PCT)
  • MGMT/Notes
    • Hydroxychloroquine – normalizes urinary porphyrin excretion and improves skin lesions
    • PCT outbreak in Turkey in the 1950s of 5000 cases
    • Bioaccumulates in adipose tissue

Dithiocarbamates (methyl isothiocyanate)

  • Effects/MOA
    • Metam sodium (dithiocarbamate) quickly degrades in soil or water to produce methyl isothiocyanate
    • Active metabolites: carbon disulfide (all dithocarbamates; thiram); methyl isocyanate (metam sodium)
  • Clinical Manifestations
    • Contact dermatitis
    • Metam sodium potent mucosal irritant
    • Disulfiram rxn possible
  • MGMT/Notes
    • Decon
    • In the same class as disulfiram (disulfiram is 2 molecules of DDC which then metabolized to CS2 and diethylamine.
    • NOT THE SAME AS CARBAMATES – dithiocarbamates have no acetylcholinesterase activity
    • Bhopal was methyl isocyanate NOT methyl isothiocyanate

Copper sulfate

  • Effects/MOA
    • Liver failure (centrilobular necrosis)
    • Intravascular hemolysis
    • Methemoglobinemia
  • Clinical Manifestations
    • MM irritation
    • Corrosive injury
    • Greenish blue emesis, hematemesis
  • MGMT/Notes
    • BAL, CaNaEDTA

Organotin compounds

Tributyltin oxide (TBTO); Triphenyltin; Cyhexatin

  • Effects/MOA
    • TBTO used as an anti-mildew control agent in interior and exterior paint
  • Clinical Manifestations
    • Potent irritant effects
    • Immunotoxic effects can occur
  • Notes
    • Prevents barnacles, algae, marine organisms

N-HEXANE aka Methyl-n-butyl ketone (MBK)

  • Effects/MOA
    • Axonopathy due to decreased phosphorylation of neurofilament proteins with disruption of the axonal cytoskeleton
  • Clinical Manifestations
    • Begins in distal extremities and progresses proximally

BUTANONE aka Methyl ETHYL ketone (MEK)

  • Uses/Notes
    • In cigarettes
    • 1, 3, 0 on NFPA
  • Clinical Manifestations
    • Irritant

Chlorinated hydrocarbons

  • Effects/MOA
    • Hepatotoxic: CCl4, benzene, pentene, vinyl chloride
    • Nephrotoxic: TOLUENE (renal tubule acidosis)
  • MGMT/Notes
    • Toluene associated with Good pasture syndrome

Methylene chloride

  • Carbon monoxide (paint thinner)


  • Systemic absorption via GI can occur and convert chlorhexidine to p-chloranaline and induce metHg

Hydrogen peroxide

  • Effects/MOA
    • Home use is 3%-8%, but is also available as  35% for “hyperoxygenation therapy”
  • Clinical Manifestations
    • 1ml of 35% liberates 100mL of Oxygen so “two sips” can lead to cerebral gas embolization
  • MGMT/Notes
    • Patients with evidence of gas embolization, place in TRENDELENBURG to prevent gas from obstructing RV flow 
    • MGMT – venous aspiration of gas, HBO


  • Effects/MOA
    • Povidone-iodide – caustic (pH~2.4)
  • MGMT/Notes
    • Oral ingestion – starch, to convert iodine to iodide → will turn effluent dark purple.
      • If no starch available, use MILK or sodium THIOSULFATE 3%


  • Clinical Manifestations
    • Skin decon with PEG 400 and WATER (NOT PEG 3350)
    • Can use isopropyl
  • MGMT/Notes
    • Rabbit syndrome – EPS like movements and chewing that resembles a rabbit
    • Burns, CNS stimulation (seizures)

Ethylene oxide

  • Uses/Notes
    • Sterilant for medical equipment
    • Risk for healthcare workers (USP 800 and IARC carcinogen)


  • Uses/Notes
    • Cold sterilant
    • Similar to formaldehyde exposure


  • Federal Insecticide, Fungicide, and Rodenticide Act of 1962
  • Established criteria for “signal word” on the insecticide which implies the degree of toxicity based on LD50
    1. Danger: Lowest LD 50 and corrosive to eyes/skin
    2. Warning: Eye issues resolve 8-21 days, severe skin irritation @ 72 hours
    3. Caution: Eye issues resolve 7 days, moderate skin irritation @ 72 hours
    4. None: Eye irritation cleared wn 24 hours and mild skin irritation

1,1-difluoroethane (DUSTING)

  • Uses
    • Keyboard dusting spray
  • Clinical Manifestations
    • Skeletal fluorosis
    • Burns (frostbite)


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