Secobarbital

5-Pentan-2-yl-5-prop-2-enyl-1,3-diazinane-2,4,6-trione

Secobarbitone, Seconal, Reds, Red Birds, Red Devils

Psychoactive Class

Depressant Sedative Anticonvulsant Anxiolytic Muscle Relaxant GABAergic

Chemical Class

Secobarbital is a short-acting barbiturate that produces potent anxiolytic, hypnotic, muscle relaxant, and amnesic effects.¹ 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.¹ 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.¹²

Dosage & Duration

Dosage

Threshold~20 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

Half-life

15-40 hours

Subjective Effects

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

Disinhibition

Suppressions

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

Anxiety suppression

Reagent Testing

Loading reagent data

Expected colorimetric results are being prepared.

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.³ This interaction increases the duration for which the chloride channel remains open, prolonging the inhibitory effect of GABA.³⁴ 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.³

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

TripSit

Tolerance

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.¹ 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.¹ Barbiturate withdrawal is medically serious and can cause a life-threatening syndrome with symptoms including anxiety, insomnia, decreased appetite, tremors, seizures, and potentially death.¹

Toxicity

Carcinogenicity

Possible

Studies have linked the use of barbiturates, particularly phenobarbital, with the development of cancer, though evidence specific to secobarbital is limited.⁵

Psychosis Risk

Delusions and confusion may occur during overdose.¹ Psychosis is a documented risk during barbiturate withdrawal syndrome and may accompany life-threatening withdrawal symptoms.⁶

Seizure Risk

While barbiturates have anticonvulsant properties during use, abrupt discontinuation in dependent individuals can cause life-threatening seizures.¹ 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 1934⁷ and later introduced it to the American pharmaceutical market in 1959 under the brand name

Legality

International

UN Convention on Psychotropic Substances 1971 (Schedule II)

By Country

United StatesSchedule II

Controlled under the Controlled Substances Act.¹ Schedule II classification indicates high abuse potential with accepted medical use under severe restrictions. Marketed as Seconal Sodium for treatment of intractable insomnia.

GermanyAnlage III BtMG

Listed in Anlage III of the Betäubungsmittelgesetz (Narcotics Act).¹⁵ Requires a special narcotic prescription form (Betäubungsmittelrezept) for medical dispensing.

SwitzerlandVerzeichnis B

Specifically named controlled substance under Verzeichnis B of Swiss narcotics legislation. Medicinal use is permitted with appropriate authorization.

CanadaSchedule IV CDSA

Controlled under the Controlled Drugs and Substances Act.¹⁴ Available by prescription with appropriate controls for Schedule IV substances.

RussiaSchedule III

Classified as a Schedule III controlled substance under Russian drug control legislation.

United KingdomClass B

Controlled as secobarbitone under the Misuse of Drugs Act 1971.¹⁶ Class B substances carry penalties of up to 5 years imprisonment for possession and up to 14 years for supply.¹⁷

References

Source Pages

Citations

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