Barbiturate Poisoning

Key points

• • Barbiturates enhance the inhibitory transmitter GABA and, in large amounts, directly open chloride channels, causing profound depression of the brain.
• • Severe poisoning causes deep coma, slow shallow breathing, low blood pressure and low body temperature, with sluggish or absent reflexes.
• • Blisters on the skin over pressure areas, the so-called barbiturate blisters, are a classic though not exclusive sign.
• • Death is usually from failure of breathing, and because barbiturates have a narrow safety margin the gap between a sleeping amount and a fatal one is small.
• • In forensic practice the manner may be suicidal, accidental or, rarely, homicidal, and the drug may be recovered from the stomach contents and viscera as part of the toxicological investigation.