II. Indications
- Status Epilepticus (esp. infants, Phenobarbital, Thiopental)
- Benzodiazepine Withdrawal
- Alcohol Withdrawal (Phenobarbital)
- Rapid Sequence Intubation (e.g. Thiopental)
III. Background
- 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
- GABA A Receptor Agonist
- Other GABA A receptor Agonists include Alcohol and Benzodiazepines
- Barbiturates have synergistic activity with Benzodiazepines
- GABA ReceptorAgonists result in prolonged duration of GABA channel opening
- Allows for Calcium influx
- GABA A Receptor Agonist
- Effects
- Sensation and motor function suppressed
- Cerebellum altered function
- Sedation
- Hypnosis
- Amnesia
IV. Medications
- Long-Acting Barbiturates (duration 10-12 hours)
- Phenobarbital
- Mephobarbital
- Short-Acting Barbiturates (duration 3-6 hours)
- Amobarbital
- Historically was used during psychoanalysis, and for determining dominant hemisphere before neurosurgery
- Pentobarbital
- Secobarbital
- Amobarbital
- Very-Short Acting Barbiturates (duration <3 hours)
- Methohexital
- Thiopental
- Has been used as induction agent in Rapid Sequence Intubation (rarely used)
- Consider for Increased Intracranial Pressure (Fastest lowering of ICP of any induction agent)
- Contraindicated in hypotensive patients or porphyria
- Risk of skin necrosis if infiltrates (highly alkalotic agent with pH 10)
- Has been used as induction agent in Rapid Sequence Intubation (rarely used)
- Propanediol Carbamates (Barbiturate-Like agents)
V. Adverse Effects
- Stupor
- Dysarthria
- Ataxia
- CNS Depression
- Respiratory Depression
- Laryngospasm
- Paraxoical activation
- Tolerance and Dependence (risk of Chemical Dependency)
VI. References
- Olson (2020) Clinical Pharmacology, Medmaster Miami, p. 56-7