In the UK, the only 'commonly' used barbs in human medicine (other than for surgical anaesthesia induction) are phenobarb, and a prodrug form of phenobarbital, primidone. AFAIK they are NOT used for insomnia, save perhaps in VERY extreme cases, I.E the worst of the worst of the most intractable insomnia that your average, or even most un-average doctor will ever see in their career.
Not sure if any of the less long-acting barbs are used for insomnia or epilepsy here, but in the case of primidone and phenobarb their primary uses are for control of epilepsy of some kinds, and in hospital for treatment of drug, or poison-induced seizures that are refractory to benzos, and I THINK some of the medium-duration ones are used to bring a patient out of status epilepticus (continuous seizures, one after the other with no recovery between them, or one long, continuous drawn out seizure), but I am not 100% sure, they may just use pheno.
I have had veronal (5,5-diethylbarbiturate), a long acting barb, its very amnestic, although euphoric, and highly abusable, much more so than I have read of peoples opinions of phenobarb, which is often regarded as just a prolonged, sedated, stupidity-inducing brick to the head in chemical form, and altogether shitty, although I haven't tried it myself.
Withdrawal from it is utter hell, opiate withdrawal is absolutely nothing compared to withdrawal from serious veronal abuse, benzo withdrawal pales, and it even makes prolonged, high-dose serious fucking abuse of GBL feel like a mild common cold in comparison, I got nicked and remanded, for non-drug related charges whilst I was physically dependent on the veronal, and they attempted to detox me on a combination of chlordiazepoxide (a shitty, piss-weak benzo) and chlormethiazole, a non-benzo, non-barb sedative, that is often used for alcoholism treatment, which is barbiturate-like in action, strong stuff, and in fact, the most euphoric downer I have ever used, and I was nevertheless in full-blown delirium tremens for weeks, if not months, psychosis, hallucinations, tachycardia, and something that to call 'anxiety' or 'panic' would be similar to calling an oxyacetylene flame 'a bit warm'.
Sent me right off the deep end, to the extent while in hospital after I eventually ODed, I drank a can of some variety of pop, then suddenly ripped it in two and rushed the two pigs that were guarding me, after the paramedics that came in the ambulance to the OD scene grassed me up for possession, and tried to use the sharp edges to slash the throats of the filth. Tried again to jump the pig that opened the cage in the back of the meatwagon with a view to beating the shit out of him.
While locked up after I got remanded, tried repeatedly to kick down the bolted steel door of the cell, and any chance I got to be exposed to any the screws, resulted in my attempting to fuck them a new arsering in the back of the head.
In short, be fucking careful with any of the barbs, including the weakish butalbital, withdrawal is the worst withdrawal you could possibly fucking imagine, and I have been through it with GBL/GHB, benzos and opiates, and another risk is that whilst tolerance rises, the lethal dosage does not.
It will take more and more to get high, but the dose it would take to kill you stays exactly the same as it was the time you take your very first dose, unlike the benzos, due to their different mode of gating the GABAa chloride channel, a benzo OD has to be bloody huge to kill you, or do much worse than KO you for an extended period of time, unless combined with alcohol or other downers/opiates, but a barb OD, a different kettle of fish entirely, and a relatively smaller OD than it takes to put you in a coma, will kill you. Taking any barb with alcohol, opiates or other downers, dose regardless is very likely to kill you outright anyway.
As for getting a script for veronal, it will not happen, period, its actually the first of the barbs to be discovered and the first to be put into medical use, but it hasn't actually been used in clinical practise for decades, and is quite simply, not available to be prescribed. I got mine as research lab grade powder, as it is used as a PH buffer for some purposes.
One other thing about barbiturates in general, is that the free barbituric acids are very poorly soluable in water, so if used for injection must be used as salts, usually the sodium salt, I couldn't get my veronal to dissolve much, if any, in water (it was the free acid, not a salt), and the salts are highly alkaline. If you miss a shot and inject it into a muscle, or under the skin, it will cause severe burns and open sores (although I never did inject the stuff)
Of course, injecting barbs....get an OD and it could drop you dead with the needle still in your arm.
My mistake.