Strychnine

Strychnine is a plant alkaloid found in the seeds of the plant Strychnos nux vomica. It is an extremely bitter substance that humans are able to detect even at minimal concentrations. The lethal dose of strychnine is as low as 30 mg.

Strychnine is a spasmodic poison that inhibits glycine receptors. In very low doses, it has a depressant effect. In large amounts, it induces spasms, increases muscle tension and causes twitching. A lethal dose can cause respiratory paralysis and respiratory arrest with subsequent death.

The antidote to strychnine is barbiturates.

Acute strychnine poisoning manifests itself as a blurring of mainly hearing (and other senses), spasms of all body muscles and seizures lasting about 2 minutes. Seizures are usually triggered by increased sensory irritation. Increased blood pressure and respiratory arrest are observed during convulsions. The person remains conscious and in great pain. The first effects of strychnine appear within half an hour.

Post-mortem rigidity is greater, sets in quickly and lasts for several days.

Strychnine is used in small quantities for hearing impairment, for visual disturbances, as rat poison and as an antidote for barbiturate poisoning.