Strychnine is short for strychnine alkaloid (C21
). It's a bitter alkaloid
drug that is used mainly as rat poison
(and has been for five centuries), but also to kill other animals that are considered pests and as a fungicide
Strychnine is derived from the seeds of a tree, Strychnos nux-vomica, that is native to Sri Lanka, Australia and India. It consists of colourless crystals or white to yellow powder.
Strychnine is very poisonous. It can be absorbed through inhalation, from the gastrointestinal and respiratory tracts and even through the mucous membranes of the eyes. It can be fatal when swallowed or inhaled, and it causes irritation to the skin when touched.
Strychnine poisoning is characterized by violent convulsions, sometimes beginning within a few minutes of ingestion. Strychnine attacks the nervous system by antagonizing the action of glycine, an amino acid that is responsible for the transmission of inhibitory nerve impulses which control muscle contraction. There is also evidence of an increase in brain levels of glutamic acid, an amino acid that acts as a transmitter for excitatory nerve impulses that excite muscle contraction. The result of these effects is that the skeletal muscles become hyperexcitable. Upon the smallest sound or movement they start contracting simultaneously without the normal restraints, leading to convulsions or seizures. Because of the convulsions respiration, a process which depends on a controlled rhythm of contraction and relaxation, becomes impossible. The resulting suffocation leads to death.
Symptoms of strychnine poisoning usually begin 15 to 30 minutes after ingestion. There may be an initial violent convulsion, but frequently symptoms begin with restlessness, apprehension, heightened sensory awareness, abrupt movements, exaggerated reflexes, muscular stiffness of face and legs, and rarely vomiting. Other symptoms of strychnine poisoning include muscular cramps (especially in the neck and back), joint stiffness, muscle twitching, restlessness, headache, severe blood-oxygen deficiency in body tissues, and cyanosis. As a secondary effect of central nervous system toxicity, kidney failure can also occur. Minor stimulation can trigger violent convulsions. Movements may be intermittent at first, but then there is hyperextension: the body arched convexly, resting on head and heels, the legs extended, arms flexed over chest or rigidly extended, fists clenched, jaw clamped, the face fixed in a grin, and the eyes bulging. When breathing stops, the victim turns blue. Between convulsions, the muscles relax completely, there is cold sweat, and the pupils may contract. After 10 to 15 minutes, the hypersensitivity returns with further convulsions. There may be one to ten such attacks before recovery or death from respiratory arrest (suffocation). The fatal dose is usually in the range of 100-200 mg, but as little as 30 mg in adults and 15 mg in children has proved fatal.
Strychnine poisoning can be treated by keeping the victim absolutely quiet and administering active charcoal to minimize absorption as a first aid measure. To prevent the seizures and suffocation, barbiturate sedatives and artificial respiration can be administered.