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what are symptoms of strychnine poisoning

Strychnine poisoning causes very fast-onset, severe nervous system symptoms, usually within 15–60 minutes after exposure, and it is a medical emergency that can be fatal without immediate care.

If you suspect strychnine exposure, call emergency services or local poison control right away and do not wait for all symptoms to appear.

Key early symptoms (minutes to an hour)

These often appear first and may quickly worsen.

  • Agitation and extreme restlessness
  • Feeling of fear, anxiety, or sense of impending doom
  • Being easily startled by light, sound, or touch
  • Stiffness or tightness in muscles, especially neck and jaw
  • Jaw tightness or lockjaw (trismus) and a forced, grimacing “sardonic smile” (risus sardonicus)
  • General muscle pain or soreness

Major muscle and nervous system signs

Strychnine blocks an important inhibitory neurotransmitter (glycine) in the spinal cord, leading to uncontrolled muscle overactivity.

  • Painful, diffuse muscle spasms or convulsions affecting the whole body
  • Spasms triggered by minor stimuli (noise, touch, bright light)
  • Rigid arms and legs with a very stiff posture
  • Arching of the back and neck (opisthotonus), sometimes so strong the body forms a bow shape
  • Characteristic “sardonic grin” due to facial muscle spasms
  • High body temperature (hyperthermia) from intense muscle activity
  • Dark urine from muscle breakdown and possible kidney damage
  • The person is often fully conscious and aware during spasms, which makes them especially distressing.

Breathing and life‑threatening symptoms

These are signs of severe poisoning and demand immediate emergency treatment.

  • Difficulty breathing or feeling unable to catch breath
  • Tightness in chest, rapid or labored breathing
  • Paralysis or severe fatigue of breathing muscles, leading to respiratory failure
  • Very frequent or almost continuous convulsions, with little relaxation between them
  • Lactic acidosis (acid build‑up in the body) and overheating from constant muscle contractions
  • Possible brain injury or death from lack of oxygen or exhaustion in high‑dose exposure

In many reported cases, death can occur within a few hours if treatment is not started quickly.

How fast symptoms appear

Timing can vary with dose and route of exposure, but broad patterns are:

  • After swallowing: symptoms usually start 15–60 minutes after ingestion
  • Onset is typically rapid (within about an hour) for most exposure scenarios
  • High-dose exposure may lead to severe breathing failure within 15–30 minutes

What to do (and not to do)

If you think someone has been exposed to strychnine:

  1. Call emergency medical services immediately.
  2. If advised by professionals, move the person away from the source and to a quiet, low‑stimulus environment (dim light, reduced noise) to avoid triggering spasms.
  3. Do not induce vomiting or force them to drink fluids unless specifically told to by medical or poison-control professionals.

Showing some of these symptoms does not prove strychnine poisoning, because other conditions (seizure disorders, tetanus, certain drug reactions) can look similar, but all require urgent medical evaluation.

Bottom note: Information gathered from public forums or data available on the internet and portrayed here.