Source & Active Principles
Source: Nux vomica seeds obtained from Strychnos nux-vomica.
Active principles: Strychnine (major toxic alkaloid) and Brucine.
Mechanism of Action
- Site of action: acts mainly on the spinal cord.
- Blocks the inhibitory neurotransmitter glycine in the spinal cord.
- Removes normal inhibition of reflex arcs → produces excessive reflex excitability.
Flow: Strychnine → blocks glycine action → loss of spinal inhibition → exaggerated reflexes → generalized convulsions → respiratory failure → death.
Fatal Dose & Period
- Fatal dose: approximately 15–50 mg.
- Fatal period: usually 1–2 hours.
Clinical Features
Onset: rapid (usually within 15–30 minutes).
Early Symptoms
- Anxiety, restlessness.
- Stiffness of muscles, twitching.