you can order benzo's online w/o a script?
Yes. But though black/grey market methods, and thats about where the line is drawn as far as specificity of discussion of said subject on BL per the user agreement.
Whats an overdose with etizolam?
If your talking about LD50 or a lethal overdose, alone not combined with other drugs, benzodiazepines have an extremely large ed50/ld50 ratio. Basically you could take a massive "overdose", and it wouldn't be lethal with pretty much any benzo alone not combined with other drugs. Not impossible, but its probably somewhere in the hundred milligram range or more.
In mice, its something like a couple hundred md/kg for diazepam and alprazolam. From a quick google search, i found 3070mg/kg orally in mice for etizolam. Usually those values are higher in humans, but impossible to determine as we don't overdose populations of humans intentionally to determine lethal doses of said drugs. Though its an interesting idea for a voluntary program for inmates on deathrow

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Basically, taken alone not in conjunction with other drugs, i'd say its pretty much impossible to overdose on etizolam. Unless you have access to hundred gram+ quantity's of it, and can get that much down. Don't let that be a rationalization for abuse/overuse though. What they lack in ld50, they more than make up for in fatal/severe physical complications of rapid discontinuation in individuals with very large tolerances. IE the drug won't kill you, the withdrawal complications will, or at least make it a medical emergency as far as seizures if you aren't deep enough in an addiction/tolerance to be at the threshold where cold turkey w/d's would cause fatal complications, like seizures.
So overdose is not really a factor with benzos taken alone, but they more than make up for that benefit in the physical complications of rapid cessation of use with a large tolerance/chronic habit. That and their lack of significant toxicity is what makes them superior to other gabergics like alcohol, with a ld50/ed50 ratio of like 3:1. 1 getting you smashed (amount depends on individual), 3x that usually is lethal for 50% of an animal population. Alcohol cessation though, is prob just as dangerous or more with a large/chronic habit compared to benzos.
Yet alcohol is legal otc. Perhaps the physical side affects factor into that though. Hangover, toxicity to liver, bad for you in large quantity's in general, make them harder to abuse. Benzo's don't really do any of that, so its easy to let your tolerance/habit climb, and think everything is just fucking dandy so long as you have access to them. Once you don't though, your completely fucked, and need to get to an emergency room asap if you have a serious tolerance/chronic habit. But that holds true for most potent gabergics, legal or not.