II. Background

  1. Strychnine tree (Strychnos nux vomica) is a tree native to Southwest Asia and Northern Australia
  2. Strychnine seeds contain an alkaloid toxin used to kill rodents
  3. Strychnine is also found in some products consumed by humans
    1. Ma Qian Zi (Chinese herbal)
    2. Salang Chai Nut (Cambodian herbal)
    3. Contaminant in production of street drugs (e.g. Cocaine, Amphetamine or Heroin)
    4. Historically used in BarbiturateOverdose

III. Pharmacokinetics

  1. Lethal dose 1-2 mg/kg (or 50-100 mg)
  2. Onset of activity: <15 to 60 minutes from ingestion
  3. Elimination half life: 10-16 hours
  4. Volume of distribution (large): 13 L/kg

IV. Mechanism

  1. Strychnine competitively blocks glycine
  2. Glycine is an inhibitory Neurotransmitter
    1. Results in Neuronal disinhibition and increased excitability (esp. in spinal column)

V. Signs

  1. Constitutional
    1. Agitation
    2. Anxiety
  2. Neuromuscular (primary effects, Tetanus-like reaction)
    1. Painful, severe Muscle spasms, rigidity, cramps with minimal triggers
    2. Hypersensitivity to external stimuli
    3. Nystagmus
    4. Dysphagia
    5. Opisthotonos (arched back)
    6. Risus Sardonicus (Sardonic Grinning)
    7. Trismus (lock jaw)
  3. Cardiopulmonary
    1. Tachypnea (may progress to apnea)

VI. Labs

  1. Serum Electrolytes (including Serum Potassium)
  2. Renal Function tests
  3. Creatinine phosphokinase

VII. Differential Diagnosis

  1. See Tetanus

VIII. Management

  1. ABC Management with Endotracheal Intubation as needed
  2. Gastrointestinal Decontamination with Activated Charcoal
    1. Indicated if ingestion within prior 1 hour
  3. Decrease Muscle Contractions, hyperthermia
    1. Reduce patient movement, stimulation
    2. Benzodiazepines
    3. Consider intubation, sedation and paralysis

X. References

  1. Otter and Tomaszewski (2019) Crit Dec Emerg Med 33(3): 28
  2. Leikin (1996) Poisoning and Toxicology, Lexi-comp, p.1016-7

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Related Studies

Ontology: Strychnine (C0202474)

Definition (MSH) An alkaloid found in the seeds of STRYCHNOS NUX-VOMICA. It is a competitive antagonist at glycine receptors and thus a convulsant. It has been used as an analeptic, in the treatment of nonketotic hyperglycinemia and sleep apnea, and as a rat poison.
Definition (CSP) extremely poisonous alkaloid which causes excitation of the central nervous system by blocking postsynaptic inhibition of neural impulses.
Concepts Pharmacologic Substance (T121) , Hazardous or Poisonous Substance (T131) , Organic Chemical (T109)
MSH D013331
SnomedCT 51200005, 354051007
LNC LP14284-1, MTHU004642
English Strychnine, Strychnidin-10-one, Strychnine [Chemical/Ingredient], strychnine, STRYCHNINE, Strychnine (substance), Strychnine product (product), Strychnine product, Strychnine product (substance)
Swedish Stryknin
Spanish estricnina, producto, estricnina (producto), producto con estricnina (producto), producto con estricnina, estricnina (sustancia), estricnina, producto (sustancia), estricnina, estricnina, producto (producto), Estricnina
Czech strychnin
Finnish Strykniini
Japanese ストリキニン, ストリキニーネ, 硝酸ストリキニーネ
Polish Nasiona kulczyby, Strychnina
French Strychnine
German Strychnin
Italian Stricnina
Portuguese Estricnina

Ontology: Toxic effect of strychnine (C0274892)

Concepts Injury or Poisoning (T037)
SnomedCT 157709000, 45519004
English Strychnine causing toxic effect, Strychnine causng toxic effect, strychnine toxicity, strychnine toxicity (diagnosis), toxicity from strychnine, strychnine poisoning, Strychnine causing toxic effect (disorder), Strychnine intoxication, Strychnine poisoning, Strychnine toxicity, Toxic effect of strychnine (disorder), Toxic effect of strychnine, Toxic effect of strychnine, NOS
Spanish efecto tóxico de la estricnina (trastorno), efecto tóxico de la estricnina, intoxicación por estricnina, toxicidad por estricnina