MBBS 2nd Profession Forensic Medicine lecture.

1. SYSTEMIC

2. • CEREBRAL
• SPINAL
• PERIPHERAL
• CARDIOVASCULAR
• ASPHYXIANTS

3. Strychnous Nux Vomica

4. Strychnous Nux Vomica
• Strychnine (kuchila) from seeds
• Active Principle
• Strychnine, Brucine
• Strychnine is 10-20times more poisonous
than brucine.
• alkaloid content of seeds is 1.8 to 5.3%.
• Uses
• Rodenticides
• Killing of stray dogs

5. Strychnine is colourless,
odourlerss rhombic prisms
and has bitter taste. Its taste
is detectable in a dilution of
1:70000.

6. Absorbtion and excretion
• Rapidly absorbed from GIT, Nasal Mucosa
and all parenteral routes.
• Rapidly metabolised in liver by microsomal
enzymes.
• Strychnine can remain in cadaver for 4
years.

7. Mechanism of action
• Acts on anterior horn cells of the
spinal cord, where glycine is a major
post-synaptic inhibitory
neurotransmitter and prevents its
effects. By inhibiting the inhibitory
transmitter it brings about excitation (
convulsions).

8. Sign and symptoms
• Bitter taste in mouth.
• Difficulty in swallowing.
• convulsions Convulsions all muscles
• Initially clonic but soon tonic
• Relaxation during interval between 2
convulsions
• Consciousness not lost & mind remains clear till
death

9. • Affects mostly extensor muscles
(Opisthotonus); Body assumes a bow like
posture. The arms are flexed over the
chestor rigidly extended, hands are tightly
clenched and legs are abducted and
extended.
• Occasionally abdominal muscle
(emprosthotonus)
• or to side (pleurosthotonus)
• Risus sardonicus - contraction of facial
muscles, widening of mouth, creases in &
around eyelids

11. FD: 30-100 mg/ kg; one crushed seed
FP: 1 to 2 hours

12. Treatment
• Control of convulsions. Ultra short acting
barbiturates.
• Gastric lavage not recommended.

13. PM appearance
• Postmortem caloricity
• Signs of asphyxia
• All internal organs congested.
• Muscles shows microscopic tears.
• Spinal cord & brain preserved

14. ML importance
• Homicide- given in alcohol to mask its
taste.
• Cattle poison
• Arrow poison
• Aphrodiasiac
• Adulterant in street drugs ( e.g. in
amphetramines, cocaine and heroin ).
• Sometimes used as stimulant and
performance enchancing drugs

15. PERIPHERAL NERVE POISON
• CURARE
• common name for arrow poisons of south
America.
• Curare is not single chemical but a group
of chemicals.
• Sources
• Chondodendron species
• Strychnous species

16. • MOA
• Non depolarising muscle relaxant.
• Absorbe through wound and abrasions.
• FD 60mg
• FP 1-2 hours

17. Sign and symptoms
• Muscular
• Eyes
• Hearing
• Swallowing
• Cns
• hypotension

18. • MLI
• Used as general anaesthesia.
• Arrow poison

19. Hemlock
• Biological Name - Conium maculatum
• All parts toxic
• MOA –
– NM junction - non-depolarising block  flaccid paralysis 
respiratory failure
– Autonomic ganglia  nicotinic  salivation, mydriasis &
tachycardia followed by bradycardia
• Features
• Ascending Paralysis
Also seen in
• Thallium (Painful, sensorimotor); Colchicine; Tick bite