Neurotoxicity with single dose intrathecal midazolam administration

Area of Science:

• Neuroscience
• Toxicology
• Electron Microscopy

Background:

• Investigating the effects of intrathecal midazolam on the spinal cord is crucial for understanding potential neurological risks.
• Midazolam is commonly used for anesthesia and sedation, but its long-term effects via intrathecal administration require detailed examination.

Purpose of the Study:

• To examine the electron microscopic alterations in the spinal cord medulla following intrathecal midazolam administration.
• To assess the neurotoxic potential of midazolam when delivered directly into the cerebrospinal fluid.

Main Methods:

• Twenty-eight rabbits were divided into two groups: one receiving intrathecal midazolam (300 microg) and a control group receiving normal saline.
• Spinal cord samples were collected 24 hours and 6 days post-administration for electron microscopic examination.
• Microscopic analysis focused on changes in neurons and myelinated axons within the medulla.

Main Results:

• Midazolam-treated rabbits exhibited severe myelin lamella separation in large axons and a honeycomb appearance.
• Degenerate vacuoles in the cytoplasm and nuclear membrane irregularities were noted in neurons of midazolam-treated groups.
• Control groups showed regular myelin lamella and nuclear membranes, with some vacuoles and edema observed in neurons.

Conclusions:

• Single-dose intrathecal midazolam administration may induce neurotoxic effects on spinal cord neurons and myelinated axons.
• These neurotoxic effects are evident at both 24 hours and 6 days after administration.
• The findings highlight the potential risks associated with intrathecal midazolam use.