Such as....
Genuinely curious.
Peace
Well meprobamate (Miltown) & Phenprobamate (Gamaquil, Isotonil, Actozine) are the only two that were great commercial successes but their are many possible analogs. It would appear that they act at the barbiturate site and in a similar manner.
I think it was recognised quite quickly that it had few advantages over the much better understood barbiturates that had been in use for over 50 years before it was introduced. Wyeth still launched it so of course randomly some doctors found it to be slightly better, equal or slightly worse than barbiturates. So it was briefly a success.
But it was never developed as far as the barbiturates although many other drug companies developed 'me too' products that essentially had no clinical advantage and never received a market licence.
By the 1960s it was revisited for it's muscle relaxant properties and quite a few prodrugs were developed. Essentially they aren't very active in their own right but are slowly metabolised into an active metabolite. Carisoprodol is simply a slow-release form of meprobamate BUT due to genetic differences, the rate at which it's metabolized can vary by a wide margin AND it can produce liver injury.
As for drugs testing. Well, since it's rather hazardous to produce and isn't very potent, nobody has ever produced it illicitly. While barbiturates are now rarely used, they ARE used and so the common 12 spot drug tests do test for them.
But the only RC that I've seen that borrows ANY of the meprobamate structure is a clomethiazole analogue. Now I have used clomethiazole to detox from alcohol dependence but again, it appears to act much like the barbiturates and is rather hazardous.
Really, their is nothing truly interesting. It's just a little historical oddity.