Nicotiana tobaccum
Nicotine is the oldest insecticide known.
The whole plant is poisonous except the ripe seeds.
Mechanism of Action - Nicotine binds stereo-specifically to nicotine receptors (acetylcholine
receptors. At moderate doses, nicotine stimulates the reticular activating system with resultant
favourable effects on memory, attention and anxiety. However, higher doses lead to tremors and convulsions through disinhibition mechanism.
Nicotine via cigarettes is rapidly absorbed directly into the arterial circulation and reaches the CNS in a few seconds. Peak behavioural and cardiovascular effects occur within a few minute.
Nicotine levels from smoking typically rise in the morning, plateau in the evening, and fall to near zero in the night.
Chronic Nicotine poisoning – causes tobacco heart (extrasystoles and angina like pain) with amblyopia.
Treatment :
Perform lavage and instill activated charcoal/ potassium permanganate
Mild to moderate intoxication atropine
Nicotine is completely eliminated from the body within 16 hours
Mecamylamine (Inversine) is a specific antagonist of nicotine but is available only in tablets. (Tablets are not suitable for a victim who is vomiting, has low blood pressure or is having convulsions.)
Replacement therapies
Nicotine gum (nicotine polacrilex) & Nicotine patch