Barbiturate

Barbiturates are Sedative-Hypnotics that have been medically available since the early 1900s
Other Sedative-Hypnotics (e.g. Benzodiazepines) were developed as an alternative to the adverse effects of Barbiturates
Mechanism
1. GABA A Receptor Agonist
  1. Other GABA A receptor Agonists include Alcohol and Benzodiazepines
  2. Barbiturates have synergistic activity with Benzodiazepines
2. GABA ReceptorAgonists result in prolonged duration of GABA channel opening
  1. Allows for Calcium influx
Effects
1. Sensation and motor function suppressed
2. Cerebellum altered function
3. Sedation
4. Hypnosis
5. Amnesia

Long-Acting Barbiturates (duration 10-12 hours)
1. Phenobarbital
2. Mephobarbital
Short-Acting Barbiturates (duration 3-6 hours)
1. Amobarbital
  1. Historically was used during psychoanalysis, and for determining dominant hemisphere before neurosurgery
2. Pentobarbital
3. Secobarbital
Very-Short Acting Barbiturates (duration <3 hours)
1. Methohexital
2. Thiopental
  1. Has been used as induction agent in Rapid Sequence Intubation (rarely used)
    1. Consider for Increased Intracranial Pressure (Fastest lowering of ICP of any induction agent)
  2. Contraindicated in hypotensive patients or porphyria
  3. Risk of skin necrosis if infiltrates (highly alkalotic agent with pH 10)
Propanediol Carbamates (Barbiturate-Like agents)
1. Meprobamate