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Secobarbital

Secobarbital molecule structureSecobarbital molecule structure
5-Pentan-2-yl-5-prop-2-enyl-1,3-diazinane-2,4,6-trione
Secobarbitone, Seconal, Reds, Red Birds, Red Devils
Chemical Class
Barbiturate

Secobarbital is a short-acting barbiturate that produces potent anxiolytic, hypnotic, muscle relaxant, and amnesic effects.citation needed Marketed under the brand name Seconal by Eli Lilly, it is used medically for the short-term treatment of insomnia and as an emergency anticonvulsant. Compared to longer-acting barbiturates, it is distinguished by its rapid onset, typically taking effect within fifteen minutes.1 It is classified as habit-forming and is internationally scheduled as a controlled substance.citation needed

Dosage & Duration

Dosage

Doses are population estimates that vary widely between individuals.

Threshold~25 mg
Light25-50 mg
Moderate50-150 mg
Strong150-300 mg
Heavy300+ mg

Duration

Onset15-60 minutes
Peak4-8 hours
Offset2-4 hours
After Effects1-24 hours
Total6-10 hours

Subjective Effects

Legacy content. A statistically backed ontology from Mindstate Design Labs is coming soon.

The secobarbital experience is dominated by dose-dependent central nervous system depression, progressing from relaxation and disinhibited, alcohol-like intoxication at lower doses to heavy sedation and hypnosis at higher ones. The compound carries anaesthetic, anticonvulsant, sedative, and hypnotic properties, and at sufficient doses it simply induces sleep or unconsciousness. Notably, it confers little analgesia; when taken in the presence of pain, paradoxical excitation can occur rather than calm sedation.

Physical

The body load centers on heavy sedation and muscle relaxation, accompanied by sluggishness, incoordination, and a staggering gait as intoxication deepens. At high or overdose-range amounts, breathing becomes shallow and respiratory depression can progress to coma and death.

Sedation

Physical depression is the defining feature of the experience and scales steeply with dose.

Muscle relaxation

Cognitive

The headspace is characterized by slowed, effortful thinking, impaired judgment, and a general blunting of anxiety and inhibition. As doses increase, thinking becomes progressively more difficult, speech slows and slurs, and memory of the period becomes unreliable, culminating in drowsiness or full loss of consciousness.

Emotional

Suppressions

Cognitive effects are broadly suppressive, deepening with dose toward unconsciousness.

Anxiety suppression

Pharmacology

Pharmacodynamics

Secobarbital acts primarily as a positive allosteric modulator at the GABA-A receptor, binding at the barbiturate site associated with the chloride ionophore.citation needed This interaction increases the duration for which the chloride channel remains open, prolonging the inhibitory effect of GABA. Secobarbital also displays antagonist activity at neuronal nicotinic acetylcholine receptors (α4 and α7 subtypes) and at several ionotropic glutamate receptors, including AMPA, kainate, and NMDA subtypes.

Pharmacokinetics

Secobarbital is metabolized primarily by hepatic microsomal enzymes, with metabolic products excreted in the urine and less commonly in the feces.1 Approximately 45-60% of the drug binds to plasma proteins. The elimination half-life ranges from 15 to 40 hours.1

Metabolitesnone documented yet

Interactions

Dangerous

Highest risk

These 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.

DissociativesStimulants

Caution

Use caution

These 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.

1,2-BenzodiazepineAbacavirAbaloparatideAbemaciclibAcalabrutinib
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Tolerance

Tolerance timelines are rules of thumb, not exact schedules, and vary widely between individuals and use patterns.

Full Tolerance
Tolerance to the sedative-hypnotic effects develops after prolonged use. The rate of tolerance development varies between individuals and depends on frequency and dosage of use.
Cross Tolerance

Barbiturates

Baseline Reset
The exact timeframe for tolerance to return to baseline is unknown.

Harm Potential

Addiction & Dependence

Psychological

Extremely High

Secobarbital is considered extremely psychologically addictive, with a particularly high risk of abuse and addiction even among barbiturates.citation needed It was widely abused recreationally in the 1960s-1980s before being largely replaced by benzodiazepines due to its high abuse potential.

Physical

Extremely High

Physical dependence develops with extended use.citation needed Barbiturate withdrawal is medically serious and can cause a life-threatening syndrome with symptoms including anxiety, insomnia, decreased appetite, tremors, seizures, and potentially death.

Toxicity

Carcinogenicity
Possible

Studies have linked the use of barbiturates, particularly phenobarbital, with the development of cancer, though evidence specific to secobarbital is limited.2

Psychosis Risk

Delusions and confusion may occur during overdose.citation needed Psychosis is a documented risk during barbiturate withdrawal syndrome and may accompany life-threatening withdrawal symptoms.

Seizure Risk

While barbiturates have anticonvulsant properties during use, abrupt discontinuation in dependent individuals can cause life-threatening seizures.citation needed Drugs that lower seizure threshold should be avoided during withdrawal. Switching to a longer-acting barbiturate such as phenobarbital may be beneficial for managing withdrawal.

History & Culture

Discovery and Development

Secobarbital was first developed in Germany in 1914 as part of ongoing barbiturate research. Eli Lilly and Company subsequently patented the compound in the United States in 1934citation needed and later introduced it to the American pharmaceutical market in 1959 under the brand name Seconal. The

Legality

International

UN Convention on Psychotropic Substances 1971 (Schedule II)

By Country

Illegal1
Netherlands flagNetherlandsIllegal
Controlled / restricted7
Canada flagCanadaRestricted
Mexico flagMexicoRestricted
New Zealand flagNew ZealandRestricted
Russia flagRussiaRestricted
Singapore flagSingaporeRestricted
Switzerland flagSwitzerlandRestricted
United Kingdom flagUnited KingdomRestricted
Prescription3
United States flagUnited StatesPrescription only
Czech Republic flagCzech RepublicPrescription only
Germany flagGermanyPrescription only

References

Source Pages

  1. DrugBank
  2. Erowid Experience Vaults: Secobarbital
  3. Erowid: Barbiturate Vault
  4. Isomer Design (TiHKAL/PiHKAL)
  5. PsychonautWiki
  6. TripSit Factsheet: Secobarbital
  7. TripSit Factsheets
  8. TripSit Wiki: Drug Combinations
  9. Wikipedia
  10. Wikipedia: Barbiturate

Citations

  1. SECONAL SODIUM (secobarbital sodium) capsule — Ranbaxy Pharmaceuticals Inc.. DailyMed / U.S. National Library of Medicine (n.d.). https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=6698bc44-b971-49cc-a5de-11e569493c591234
  2. Phenobarbital (Group 2B) — Overall Evaluations of Carcinogenicity, IARC. NCBI Bookshelf / IARC (n.d.). https://www.ncbi.nlm.nih.gov/books/NBK533499/1
  3. Death with Dignity Act. Washington State Department of Health (n.d.). https://doh.wa.gov/data-and-statistical-reports/health-statistics/death-dignity-act1
  4. Vermont Statutes Annotated, Title 18, Chapter 113 — Patient Choice and Control at End of Life (Act 39, 2013). Vermont Legislature (n.d.). https://legislature.vermont.gov/statutes/fullchapter/18/1131
  5. Controlled Drugs and Substances Act. laws-lois.justice.gc.ca (n.d.). https://laws-lois.justice.gc.ca/eng/acts/C-38.8/section-sched95660.html1
  6. Controlled Drugs and Substances Act (S.C. 1996, c. 19) — Schedule IV. Government of Canada, Department of Justice (n.d.). https://laws-lois.justice.gc.ca/eng/acts/c-38.8/page-12.html1
  7. Government Regulation No. 463/2013 Coll., on Lists of Addictive Substances. e-sbirka.cz (n.d.). https://www.e-sbirka.cz/sb/2013/463?zalozka=text1
  8. Government Regulation No. 463/2013 Coll., on Lists of Addictive Substances. e-sbirka.cz (n.d.). https://www.e-sbirka.cz/sb/1998/167?zalozka=text1
  9. Anlage III BtMG. gesetze-im-internet.de (2019). https://www.gesetze-im-internet.de/btmg_1981/anlage_iii.html12
  10. Ley General de Salud, artículo 245, fracción II, y artículo 247. diputados.gob.mx (n.d.). https://www.diputados.gob.mx/LeyesBiblio/pdf/LGS.pdf1

Further Reading

  1. Drugs.com: Secobarbital Interactions

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Recent changes8 human edits · latest

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21 August 2026

  1. Lyrea · Changed a word in Dosage & Duration › Routes 1 › Dose ranges › Threshold

24 January 2026

  1. Josie Kins · Updated the article · also 1,4-Butanediol, 1B-LSD, 1cP-AL-LAD and 573 more

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