Sodium thiopental, better known as Sodium Pentothal (a trademark of Abbott Laboratories), thiopental, thiopentone sodium, or Trapanal (also a trademark), is a rapid-onset short-acting barbiturate general anaesthetic. Thiopental is a core medicine in the World Health Organization’s “Essential Drugs List”, which is a list of minimum medical needs for a basic healthcare system. It is also usually the first of three drugs administered during most lethal injections in the United States.

Barbiturates

Barbiturates are a class of drugs that act on the GABA_A receptor in the brain and spinal cord. The GABA_A receptor is an inhibitory channel that decreases neuronal activity, and barbiturates enhance the inhibitory action of the GABA_A receptor. Barbiturates, benzodiazepines, and alcohol all bind to the GABA_A receptor. Barbiturates that act on the barbiturate binding site of the GABA_A receptor directly gate the chloride ion channel of the GABA_A receptor, whereas benzodiazepines acting on the benzodiazepine site on the GABA_A receptor increase the opening frequency of the chloride ion channel. This explains why overdoses of barbiturates may be lethal whereas overdoses of benzodiazepines alone are typically not lethal. Another explanation is that barbiturates can activate GABA receptors in the absence of the GABA molecule, whereas benzodiazepines need GABA to be present to have an effect: this may explain the more widespread effects of barbiturates in the central nervous system. Barbiturates have anesthetic, sedative, anxiolytic, anticonvulsant and hypnotic properties. Barbiturates do not have analgesic effects.

Uses

Anesthesia

Thiopental is an ultra-short-acting barbiturate and has been used commonly in the induction phase of general anesthesia. Its use in the United States and elsewhere has been largely replaced with that of propofol. Following intravenous injection the drug rapidly reaches the brain and causes unconsciousness within 30–45 seconds. At one minute, the drug attains a peak concentration of about 60% of the total dose in the brain. Thereafter, the drug distributes to the rest of the body and in about 5–10 minutes the concentration is low enough in the brain such that consciousness returns.

A normal dose of thiopental (usually 4–6 mg/kg) given to a pregnant woman for operative delivery (caesarian section) rapidly makes her unconscious, but the baby in her uterus remains conscious. However, larger or repeated doses can depress the baby.^{[citation needed]}

Thiopental is not used to maintain anesthesia in surgical procedures because, in infusion, it displays zero-order elimination kinetics, leading to a long period before consciousness is regained. Instead, anesthesia is usually maintained with an inhaled anesthetic (gas) agent. Inhaled anesthetics are eliminated relatively quickly, so that stopping the inhaled anesthetic will allow rapid return of consciousness. Thiopental would have to be given in large amounts to maintain an anesthetic plane, and because of its 11.5–26 hour half-life, consciousness would take a long time to return.

In veterinary medicine, thiopental is used to induce anesthesia in animals. Since thiopental is redistributed to fat, certain breeds of dogs – primarily the sight hounds – can have accelerated recoveries from thiopental due to their lack of body fat and their lean body mass. Similarly, overweight or obese animals will have prolonged recoveries from thiopental. Thiopental is always administered intravenously, as it can be fairly irritating; severe tissue necrosis and sloughing can occur if it is injected incorrectly into the tissue around a vein.

Truth serum

Thiopental (Pentothal) is still used in some places as a truth serum to weaken the resolve of the subject and make them more compliant to pressure.^[21] The barbiturates as a class decrease higher cortical brain functioning. Some psychiatrists hypothesize that because lying is more complex than telling the truth, suppression of the higher cortical functions may lead to the uncovering of the truth. The drug tends to make subjects loquacious and cooperative with interrogators; however, the reliability of confessions made under thiopental is questionable. Sodium thiopental features as a truth serum in several Hollywood films, in comics and other literature, and even in popular music.

Me: Now we see from another source, the io9 on what they say

….Like heroin, sodium pentothal is a brand name. The drug was manufactured and trademarked by Abbott Laboratories, and its free-for-all name is sodium thiopental. It’s a barbiturate, a drug that acts on the central nervous system, which it depresses to calm anxiety, induce drowsiness, eliminate pain, and sometimes entirely knock someone out. That is not why it’s become world famous. Sodium pentothal made its name in detective, spy, and pulp novels, where it was famously used as a ‘truth serum.’ Novelists weren’t making it up. Psychiatrists and police officers both swore by it in the first half of the twentieth century – but whether it which of its powers were fact and which were fiction is still debated.

But Does It Work?

Well, it might. If someone is dead set against telling your their secrets it might make them so disoriented that they’ll spill something. It’s just that, to make it at all effective, you have to positively know what you’re looking for already, because if they tell you that, they’ll generally tell you a lot of other things as well. And you’ll have to work on your tone, because someone under the influence of any of the ‘truth drugs’ will most likely tell you what you want to hear. The drugs make people a little more obliging, but mostly they suppress the parts of the brain that have to kick into gear if a person is to assess what’s wrong with a question, articulate it, and assert themselves to their questioner. It’s easier just to let their imagination go with the flow and tell the questioner exactly what they want to hear.

That is not a problem if all the questioner wants is a confession, right or wrong. If they want information, though, sorting out a person being honest, being imaginative, misunderstanding the question, and outright lying because it’s easier, is tough to do. One of the reasons Multiple Personality Disorder was nailed down as only being cause by severe child abuse is Doctor Wilbur insisting that that was the only cause. Earlier patients mentioned mildly traumatic events in childhood but not necessarily direct abuse, nor was that trauma the only cause of the split in personality. Wilbur then founded an organization which trained therapists to use drugs and hypnosis and probe for childhood abuse. After many leading questions, patients would finally go along with what their therapists were saying, the therapist would declare that a memory had finally be recovered, and the cause of the illness would be reinforced. Recovered memory abuse would range from Sybil’s false memory of being flown to (occupied) Holland during World War II to help an English officer smuggle out his wife, all while in the persona of a twelve-year-old, to fantastic stories of Satanic cults sacrificing humans inside regular towns. When cases against parents started falling through, and lawsuits started piling up, truth drugs fell from favor fast. Meanwhile, when the Supreme Court declared that confessions under the influence were coerced, which was unconstitutional, and the easy confessions turned into a lot of freed prisoners, with occasional scrambles to collect old evidence.

In the end, sodium pentothal proved useless not because no one could get information, but because everyone could get too much. It gave questioners information in endless streams that were near-impossible to sort into fact and fiction. It dangled exactly the reply people wanted in front of them, but made anyone who was informed about the drug question if it was only there because they wanted it. It can’t offer any certainty that information gotten out of a person was anything more than fantasy. And since certainty is what ‘truth serum’ is supposed to be all about, then it definitively fails.

Me: I guess I was wrong and maybe should change the title of the article. It seems that the chemical compound can not really get the truth from someone else, mainly because the person will indeed become more talkative, but in the pricess will say many things and the person asking the question will not be able to separate the answers they want from the other things the person being questioned says.