Final answer:
The toxic metabolite of meperidine that can lower the seizure threshold is normeperidine. Normeperidine's excitatory effects on the central nervous system increase the risk of seizures. Anticonvulsants may be used to treat such seizure activity.
Step-by-step explanation:
The toxic metabolite of meperidine is normeperidine, which is known for its potential to lower the seizure threshold. Meperidine is a synthetic opioid used for the treatment of moderate to severe pain but its metabolite can cause excitatory effects on the central nervous system. This can lead to an increased risk of seizures, particularly when used in high doses or for extended periods. In treating patients who experience seizures potentially induced by normeperidine, anticonvulsants like diazepam may be administered to stabilize the patient and control the seizure activity. Furthermore, the ability of toxic metabolites to cross the blood-brain barrier is significant in the assessment of their central nervous system effects.