Strychnine poisoning: It is an alkaloid derived from the seeds of the tree Strychnos nux-vomica. The potentially fatal dose of strychnine is approximately 50-100 mg (1 mg/kg) and fatal period is 1-2 hours. Strychnine competitively antagonizes glycine, an inhibitory neurotransmitter released by postsynaptic inhibitory neurons in the spinal cord. Muscular stiffness and painful cramps precede generalized muscle contractions, extensor muscle spasms, and opisthotonus. Death usually is caused by respiratory arrest that results from intense contraction of the respiratory muscles. Ref: Nordt S.P. (2012). Chapter 145. Strychnine. In K.R. Olson (Ed), Poisoning & Drug Overdose, 6e.