Benzodiazepine
Definition
Fused benzene plus seven-member diazepine ring. Allosteric modulator of GABA-A at the alpha-gamma interface. Reversed by flumazenil.
- Core structure
- Fused benzene ring plus seven-membered diazepine ring
- Mechanism
- Allosteric modulator of GABA-A at the alpha-gamma interface
- Reversal agent
- Flumazenil
- Use class
- Sedatives, hypnotics, anxiolytics
Common questions
Why does GABA-A allosteric modulation distinguish benzodiazepines from barbiturates in overdose severity?+
Benzodiazepines only enhance GABA-A channel opening in the presence of GABA itself, giving a ceiling effect, whereas barbiturates can open the channel directly at high concentration, which is a large part of why pure benzodiazepine overdose is comparatively less often fatal on its own than barbiturate overdose.
Why is flumazenil not routinely given for a suspected benzodiazepine overdose?+
It can precipitate acute, sometimes life-threatening withdrawal seizures in a patient who is benzodiazepine-dependent or has co-ingested a pro-convulsant drug, so its use is generally reserved for carefully selected cases rather than applied as a default antidote.
Related terms
- Barbiturate
- Cyclic ureide derivative of barbituric acid. Potentiates GABA-A. Sub-classed by duration of action: long (phenobarbital), intermediate (amobarbital), short (secobarbital, pentobarbital) and ultrashort...
- FPN Reagent
- Ferric chloride, perchloric acid and nitric acid mixture. Red to orange-red colour with phenothiazines (chlorpromazine and relatives). Screen of choice for major...
- Schedule H1
- Forty-six substances notified by the 2013 amendment (Drugs and Cosmetics Fourth Amendment Rules, 2013, GSR 588(E) dated 30 August 2013, in force...
- Sedative-Hypnotic
- CNS depressant. Sedative dose calms (anxiolysis); hypnotic dose induces sleep; higher doses cause anaesthesia, respiratory depression and death.
- Tranquillizer
- Older umbrella term. Minor tranquillizers (benzodiazepines) treat anxiety. Major tranquillizers (phenothiazines, butyrophenones) are antipsychotics.
- Z-Drug
- Non-benzodiazepine hypnotic (zolpidem, zopiclone, eszopiclone) that binds the alpha-1 subunit of GABA-A selectively. Same date-rape and stupefying-robbery potential as the BZDs.
- Zwikker / Dille-Koppanyi Reagent
- Cobalt salt (nitrate or acetate) plus isopropylamine. Violet to blue-violet colour with barbiturates. Workhorse barbiturate screen since the 1940s.