Please note: Dosage equivalents are provided for certain drugs below and are denoted as unit equivalents, i.e. one unit of drug x is roughly the equivalent as one unit of drug y, where the dosage equal to one unit varies.
Barbiturates are drugs that act as central nervous system (CNS) depressants, and by virtue of this they produce a wide spectrum of effects, from mild sedation to anesthesia. Some are also used as anticonvulsants.
Barbiturates are believed to be GABA (gamma-aminobutyric acid) agonists, acting on the GABA-A receptor. GABA is the principal inhibitory neurotransmitter in the mammalian CNS.
Barbiturates are derivatives of barbituric acid.
Currently barbiturates are used both in their traditional roles and as lethal substances in the cases of assisted suicide, euthanasia and capital punishment by lethal injection, usually when administered alongside a muscle relaxant.
Sometimes two or more barbiturates are combined in a single tablet or capsule; perhaps the most well-known of these combinations is Tuinal, which consists of amobarbital and secobarbital in equal proportions.
These drugs have now fallen out of favour as they are both highly addictive and potentially toxic to the point of being fatal in many cases. They were discovered on the fourth of December, 1863 by one Adolf von Baeyer, who named the family after the day of St. Barbara after the day on which he made the discovery; however, it is possible that he could have named the drugs after his girlfriend Barbara - no-one truly knows. They started to fall out of favour in the 1950s and 1960s when their side effects were truly picked up on.
Judy Garland, Marilyn Monroe and Jimi Hendrix were among the many who died from barbiturate overdoses, as did George Sanders and Kenneth Williams.
Allobarbital
I know very little about this drug; all I can say for sure is that it can be used as a sedative and/or as a hypnotic and that it has a medium to long lasting half life.
Amobarbital (Amylobarbitone)
Née amylobarbitone. The drug is a sedative hypnotic and analgesic but exhibits no anxiolytic properties. It is approved for the treatment of anxiety, insomnia, epilepsy and catatonic mutism; combined with caffeine, the drug can also treat somnolence. It also works as a truth serum, making the patient more pliable to questioning.
Aprobarbital
No current data.
Barbexaclone
Introduced in 1983, this drug is currently unavailable both in the UK and in the USA. Essentially, it is a salt compound of phenobarbital and propylhexedrine (a sympathomimetic amine); it is, seemingly, just as effective as phenobarbital yet far better tolerated. 10mg of this drug is roughly equal to 6mg of phenobarbital.
Barbital (Barbitone)
Née barbitone. Barbital was the first heavily marketed barbiturate, created in 1902 and introduced to the market a year later. The primary use was as a hypnotic to tackle nervous insomnia and the drug was considered to be a great advancement over current drugs, namely bromides, exhibiting a massive improvement in palatability, fewer side effects and a therapeutic dose that was far bellow toxicity. However, fatal overdoses were all too often.
Butabarbital
Prescribed primarily as a hypnotic and unfortunately was highly hazardous to the point of fatal when mixed with alcohol. It was also used as a tranquilliser to combat panic attacks and as a pre-surgery sedation.
Butalbital
Interestingly, this drug has the same chemical formula as talbutal and yet has a different structure. It exhibits a moderate duration of effectiveness and can be easily mixed with other drugs to treat localised pains, such as headaches. As with other barbiturates, the drug is extremely dangerous when combined with alcohol and is highly addictive.
Butobarbital
Prescribed to treat extreme insomnia.
Cyclobarbital (Cyclobarbitol; Cyclobarbitone)
Née cyclobarbitol, cyclobarbitone.
Ethallobarbital
No current data.
Heptabarbital -
No current data.
Hexobarbital
No current data.
Metharbital
Introduced in 1952, metharbital is used for the management of epilepsy (being an anticonvulsant). It exhibits similar properties to phenobarbital.
Methohexital
Marketed under the brand of Brevital, this drug was primarily used as a powerful but short acting anaesthetic and exhibited similarities to the drug thiopentone. It is only ever used in emergencies under strict supervision either within a hospital or an ambulance. It's half life is, ±2.7m, 5.6m.
Methylphenobarbital (Mephobarbital)
Née mephobarbital, this drug was marketed under the name of Mebaral. This drug exhibits sedative, anxiolytic and anticonvulsant effects. It was introduced in 1935 and is the N-methylated analogue of phenobarbital; it subsequently has similar characteristics to phenobarbital in terms of side effects, effectiveness and so on. The drug was discontinued in the UK in 2001.
Pentobarbital
Introduced in 1930, pentobarbital is a short acting drug with a half life of 35 to 50 hours and was, among others, marketed as Nembutal. It is primarily used to treat seizures and sedation; it can also be used as a short term hypnotic. It can also be applied to relieve intracranial pressure in Reye's syndrome, to induce a coma in patients with cerebral ischemia and to help patients with traumatic brain injury. In veterinary medicine, the drug can be used as an anaesthetic and is dubbed Sagatal; it can also be used in veterinary euthanasia, usually when mixed with other drugs in injectable solutions, branded as Euthasol, Euthatal, Beuthanasia-D and Fatal Plus to name but a few.
Phenobarbital (Phenobarbitone)
Slightly acidic, phenobarbital is also known generically as phenobarbitone and commercially as Luminal. It is used as a hypnotic, sedative and anticonvulsant medicine. It was widely used from the 1930s until the 1960s when more modern hypnotics (such as benzodiazepines) were introduced. Although it is still used commonly by veterinarians, phenobarbital is more tightly controlled in both the UK and the USA.
Proxibarbal
No current data.
Reposal
No current data.
Secobarbital (Quinalbarbitone)
Née quinalbarbitone, brand names include Seconal and Tuinal. It exhibits anaesthetic, anticonvulsant, sedative and hypnotic properties and is used to combat epilepsy, insomnia (on a short term basis only and then only to patients habituated to the drug family) and in addition to this, the drug acts as a strong anaesthetic and anxiolytic drug. Recreationally, it was nicknamed as "reds", "seccies" and "dolls", amongst others. The drug was commonly used in cases of assisted suicide, euthanasia and capital punishment by lethal injection until it was discontinued in May 2001, whereupon the drug pentobarbital was adopted for the same purposes. Production of secobarbital resumed in 2006.
(Sodium) Thiopental
Marketed under the brand Sodium Pentothal and discovered in the early 1930s, this medicine is also widely known as thiopental, thiopentone sodium and trapanal. It is a short acting but very powerful and takes hold very rapidly; it is used as a general anaesthetic. Upon intravenous injection, it only takes between 30 to 45 seconds to render a patient unconscious. The concentration within the brain peaks after approximately one minute [after the injection] at approximately 60% of the dose; thereafter it diffuses into the body, leaving the patient able to regain consciousness after between 5 and 10 minutes. It has a half life of about 11.5 to 26 hours and as such large doses to keep a patient unconscious would lead to a very gradual return to consciousness. Anaesthesia is instead maintained with an inhaled anaesthetic agent. Additionally, this drug can be used to induce comas, despite the fact that it's effects are extremely short lived in moderate doses. When administered in high doses, the patient enters a medical coma, which depresses activity and combats intracranial pressure and inflammation. It has been found that for this purpose, this drug has been shown to be superior to pentobarbital. On top of this, it also functions at extremely high doses as a fatal medicine in the interests of assisted suicide, euthanasia and capital punishment by lethal injection and is also useful as a truth serum.
Talbutal
Also known as 5-allyl-5-sec-butylbarbituric acid (try remembering that one!) and marketed as Lotusate and had a short to medium duration of effect.
Thiobarbital
No current data.
Vinbarbital
No current data.
Vinylbital (Butylvinyl)
Primarily used as a sedative, Vinylbital is also known as Butylvinyl.