1. Strychnos Nux Vomica seeds contain the toxic alkaloids strychnine and brucine, which act as spinal poisons by competitively blocking inhibitory receptors in the spinal cord, causing widespread muscle spasms and convulsions. 2. Curare acts as a peripheral nerve poison by blocking nicotinic acetylcholine receptors at the neuromuscular junction, causing flaccid paralysis. 3. Conium Maculatum (Hemlock) contains the toxic alkaloid coniine and causes progressive motor paralysis through its effects.

1. Spinal poisons
Strychnos Nux Vomica
Curare
Conium Maculatum (Hemlock)

2. Strychnos Nux vomica

4. Seeds
• Flat , circular discs , slightly convex on one side
• Concave on other
• 2.5 cm D, 6 mm thickness
• Ash grey or light brown in colour
• Shining surface , and covered with radiating
silky fibres
• Hard tough and difficult to pulvarize

8. Fruits
• Round
• Hard
• Slightly rough
• Glossy orange
• 4-5 cm
• Jelly like white or pale yellow pulp pulp has
very low strychnine content
• 3- 5 seeds

13. • Strychnine /Kuchila  powerful alkaloid
• The seeds of the ripe fruit are poisonous
• Contains
1. Strychnine 1.5%
2. Brucine 1.5%
3. Loganin (glucoside)

14. • Strychnine  colourless, odourless, rhombic
prisms , having an intensely bitter taste
• Bark/wood/leaves contains only brucine
• All parts of the tree are toxic
• Brucine is similar to strychnine in composition
and action
• Strychnine is 10 – 20 times more poisonous
than brucine

15. • Strychnine is used as a respiratory stimulant ,
rodenticide , and for killing stray dogs

17. Metabolism
• All mucous membrane absorbs strychnine
• Much is taken up by liver and muscles 
destroyed or later released
• This release can cause convulsions on the
second or third day of poisoning after
sedation is discontinued
• 80% is oxidised mainly in liver
• Excreted by kidneys , traces in saliva , milk ,
bile

18. • It may be found in cadaver upto 4 years

19. Action
• Competitively blocks  Anterior horn cell
Post ganglionic receptor site in the spinal cord
• Prevents the effect of glycine (presumed
inhibitory transmitter )
• Widespread inhibition of spinal cord results in
release excitation
• Action is particularly noted in the anterior
horn cells
• It stimulates cerebral cortex

20. • If swallowed uncrushed  no poisonous
action
• Crushed  symptoms within 1 hour or more
• Alkaloid swallowed  5 to 15 min

21. Symptoms
• Bitter taste in mouth
• Sense of uneasiness
• Restlessness
• Feeling of suffocation
• Fear and difficulty in swallowing
• Convulsions follow increased acuity of
perception , increased rigidity of muscles , and
muscular twitchings

22. • Convulsions by direct action on reflex
centers of spinal cord and affect all the
muscles at a time
• First clonic  later become tonic
• Face cyanosed, anxious look ,eyes staring , eye
balls prominent , pupils are dilated
• Risus sardonicus  contaction of jaws and
facial muscles in which the corners of the
mouth are drawn back

23. • Mouth  covered with froth frequently blood
stained
• Convulsions are most marked in Anti gravity
muscles
• So the body typically arches in hyper
extension  Opisthotonus
• Emprosthotonus
• Pleurosthotonus

24. • Consciousness is not lost and mind remains
clear till death
• Suffering during spasm is severe , and the
patient is conscious of impending danger of
death
• Duration of convulsions vary from half to 2
min

25. • In between convulsions patient may be
normal
• After 5 – 15 min  /slightest impulse 
sudden noise, air current, touching  another
convulsion occurs
• Death usually occurs after 4 – 5 convulsions
• Patient cannot breath  diaphragm and
thoracic muscles are fully CONTRACTED

26. • Hypoxia causes mudullary paralysis and death
• Non fatal  convulsions and spasms stops
within 12 – 24 hours and recovery takes place
in a day or two

27. • Fatal dose  50 – 100 mg / one crushed seed
• Fatal period  1 -2 hours

28. Treatment
• Symptoms are treated before disease
• Effective control of convulsions
• Dark room
• Diazepam , phenobarbital , GA, Sch, Curare ,
gallamine, pancuronium
• Inhalation anaesthetics are of little value

29. • Antidotes  short acting barbiturates like
pentobarbital sodium or sodium amytal
• 0.3 – 0.6 g iv
• Stomach wash  warm water , dilutue
solution of potassium permanganate ,
activated charcoal /tannic acid
• Acidifying the urine will increase the excretion
of strychnine

30. PM appearances
• Not characteristic
• Rigor mortis appears early but not necessarily
prolonged
• There may be signs of asphyxia
• Extravasated blood may be found in muscles
• Hemorrages may be seen under the peritoneal
coat of stomach

31. • Mucosa of stomach and duodenum may show
patches of ecchymosis and congestion
• Lungs, liver , brain and spinal cord are
congested

32. Physiological test
• Suspected material  dorsal lymph sac of frog
 convulsions

33. Circumstances of poisoning
• Suicide is rare because of painful death

34. Peripheral nerve poisons

35. CURARE
• Found in various species of strychnos
• Curarine  active principle
• Action  entirely peripheral at the myoneural
junction  blocks post synaptic nicotinic
Ach receptors  flaccid paralysis of skeletal
muscles
• Not poisonous when swallowed
• Absorbed through wounds

36. Symptoms
• Paralysis
• Death from asphyxia
• Mydriasis
• Liberated histamine
• Mind clear till end
•

37. curare
• Fatal dose  60 mg
• Fatal period  1-2 hours

38. Treatment of cuare
• Atropine 0.6 – 1.2 mg
• Neostigmine 5 – 10 mg
• Physostimine  3 ml of 1:200 solution iv

39. PMA
• Those of asphyxia
• Its used as arrow poison

40. CONIUM MACULATUM (HEMLOCK)

47. • Devil's Bread" or "Devil's Porridge", there are
also Poison Parsley, Spotted Corobane, and
Spotted Hemlock. The seeds are sometimes
called Kecksies or Kex.
• Conium comes from the Greek konas
(meaning to whirl), in reference to vertigo one
of the symptoms of ingesting the plant

48. • Contains coniine
• Highest in unripe fruits and seeds
• Root
• Leaves
• Fatal dose  60 mg of coniine

49. Signs and symptoms
• Fresh leaves  Nauseating taste , mousy
odour
• Progressive motor paralysis