It can be used as an antidote for strychnine poisoning. Mephenesin however presents with the major drawbacks of having a short duration of action and a much greater effect on the spinal cord than the brain, resulting in pronounced respiratory depression at clinical doses and therefore a very low therapeutic index. It is especially dangerous and potentially fatal in combination with alcohol and other depressants.
The passage describes mephenesin's role as a treatment for strychnine poisoning, emphasizing its short duration of action, strong effect on the spinal cord, and dangerous interactions with alcohol or other depressants.