WARNINGOVERDOSE, COMBINATIONS, & WITHDRAWAL CAN BE FATAL
High doses alone or ordinary doses in combination with other depressants can fatally stop breathing. After prolonged dependency, stopping suddenly can cause seizures, delirium, or death.
Pentobarbital
Pentobarbital is a short-acting barbiturate1 that produces potent sedative, hypnotic, anxiolytic, muscle relaxant, and amnesic effects. It is used medically for the short-term treatment of insomnia,1 as an emergency anticonvulsant,1 and to induce medical comas.2 Pentobarbital acts on GABA-A receptors at a distinct allosteric site from benzodiazepinescitation needed and is characterized by a relatively prompt onset of action. It is classified as habit-forming1 and is internationally scheduled as a controlled substance.citation needed
Dosage & Duration
Dosage
Doses are population estimates that vary widely between individuals.
Duration
Subjective Effects
Legacy content. A statistically backed ontology from Mindstate Design Labs is coming soon.
The experience is dominated by heavy central nervous system depression, producing drowsiness, relief of tension and nervousness, and an intoxication broadly comparable to alcohol in character. Unlike opioids, pentobarbital provides little pain relief, and its use in the presence of significant pain can paradoxically result in excitation rather than calm. As the dose climbs, coordination, speech, and judgment deteriorate progressively, and at overdose levels the state shades into stupor, coma, and dangerously shallow breathing.
Physical
The body feels heavy, relaxed, and sedated, with incoordination and a staggering gait emerging as doses increase. Breathing becomes shallow at high doses, which is the primary driver of its overdose lethality.
Cognitive
The headspace is slowed and clouded, with sluggish thinking, impaired judgment, and a marked reduction in anxiety and tension. Recall of the period under the drug's influence becomes unreliable at higher doses.
Suppressions
Pharmacology
Pharmacodynamics
Pentobarbital acts primarily as a positive allosteric modulator of the GABA-A receptor, binding at the barbiturate site to prolong the duration of chloride ion channel opening.citation needed At higher concentrations, it is capable of directly activating the channel in the absence of GABA.3 This potentiation of GABAergic inhibitory tone is associated with marked decreases in GABA-sensitive neuronal calcium conductance. Pentobarbital also directly inhibits excitatory AMPA-type glutamate receptors, suppressing glutamatergic neurotransmission,4 and acts as an antagonist at NMDA receptors, kainate receptors, and neuronal nicotinic acetylcholine receptors (α4 and α7 subunits).citation needed
Pharmacokinetics
Pentobarbital undergoes first-pass metabolism in the liver and possibly the intestines via the hepatic microsomal enzyme system, with subsequent renal excretion.citation needed Oral bioavailability is approximately 70-90%, with 45-60% protein binding. The elimination half-life is dose-dependent, ranging from 5 to 50 hours.
Dangerous
Highest riskThese combinations are considered extremely harmful and should always be avoided. Reactions to these drugs taken in combination are highly unpredictable and have a potential to cause death.
Caution
Use cautionThese combinations are not usually physically harmful, but may produce undesirable effects, such as physical discomfort or overstimulation. Extreme use may cause physical health issues. Synergistic effects may be unpredictable. Care should be taken when choosing to use this combination.
Tolerance
Tolerance timelines are rules of thumb, not exact schedules, and vary widely between individuals and use patterns.
Barbiturates
Harm Potential
Addiction & Dependence
Psychological
Extremely HighPentobarbital is deemed extremely psychologically addictive, with compulsive redosing commonly reported.citation needed Short-acting barbiturates carry particularly high abuse potential, and the substance was widely abused beginning in the late 1930s.
Physical
Extremely HighPentobarbital produces severe physical dependence with chronic use.citation needed Barbiturate withdrawal is medically serious and can cause a life-threatening syndrome including seizures, psychosis, and death with abrupt discontinuation.
Toxicity
Respiratory depression is the primary acute toxicity and can progress to respiratory arrest and death, particularly at higher doses or when combined with other CNS depressants.citation needed
Studies have linked barbiturate use with the development of cancer,citation needed though phenobarbital has been particularly implicated; evidence specific to pentobarbital is limited.
Psychosis Risk
Psychosis may occur as part of the life-threatening barbiturate withdrawal syndrome in dependent individuals.citation needed During intoxication, delusions of sobriety are reported at heavy doses, representing impaired reality testing rather than true psychosis.
Seizure Risk
Pentobarbital has anticonvulsant properties and suppresses seizures during use. However, abrupt discontinuation in dependent individuals may cause potentially fatal seizures as part of the withdrawal syndrome.citation needed Drugs that lower seizure threshold should be avoided during withdrawal.
History & Culture
Discovery and Development
Pentobarbital was developed by chemists Ernest H. Volwiler and Donalee L. Tabern at Abbott Laboratories in 1930.5 That same year, physician John S. Lundy began clinical use of the compound and coined the brand name Nembutal, an amalgamation derived from the
Legality
International
UN Convention on Psychotropic Substances 1971 (Schedule III)
By Country
SwitzerlandIllegal
RussiaRestricted
United KingdomClass B
References
Source Pages
Citations
Further Reading
Article Status
Step 1 · Automated synthesisAn autonomous workflow built by Josie Kins compiled this article's foundation from information published across the web.
- LStep 2 · First-pass review
A first pass manual review and edit of article prose and copy has been performed by subject-matter expert Lyrea. This does not guarantee factual accuracy. An additional human review for each of this article's citations is yet to be performed.
- Step 3 · Citation reviewPending
No one has reviewed this article's citations yet. That second pass checks each claim against the source it cites.
Suggest an edit
Spotted a mistake, an outdated claim, or something missing from the Pentobarbital article? Send the editors a private note. Feedback lands in a moderation queue and is never shown on the site.
Wish to give generalised feedback? You can do so here.
