Pharmacology Barbiturate Toxicity of various barbiturates acute toxicity coefficients (ATC) and absolute toxicity levels (<kLog mg/L)

[Flynnal]

Just thought I'd add some interesting things I found about barbiturates through a SAR engine that came up with a laundry list of interesting figures. The figures regarding acute toxicity were rather interesting. Many of the drugs considered weak or less potent actually turned out to be exceedingly toxic.

Barbiturate Toxicity:

ORAL BARBITURATES
CRITICAL INFO:

kLog mg/L: The lower the number, the higher the absolute acute toxicity of the drug.
Acute toxicity coefficient (ATC) percentage: The higher the number the higher the relative acute toxicity.

Vinylbital
kLog mg/L: -1.99
ATC percentage: 58.9%

Talbutal
kLog mg/L: -2.0
ATC percentage: 58.59%

Aprobarbital
kLog mg/L: -2.06
ATC percentage: 57.11%

Secobarbital
kLog mg/L: -2.07
ATC percentage: 56.81%

Pentobarbital
kLog mg/L: -2.11
ATC percentage: 55.79%

Secbutabarbital
kLog mg/L: -2.19
ATC percentage: 53.85%

Amobarbital
kLog mg/L: -2.25
ATC percentage: 52.29%

Phenobarbital
kLog mg/L: -2.42
ATC percentage: 47.98%

Cyclobarbital
kLog mg/L: -2.73
ATC percentage: 40.17%

Barbital
kLog mg/L: -2.89
ATC percentage: 35.96%

Most toxic barbiturate of this set:
Vinylbital

Lease toxic barbiturate of this set:
Barbital

Note: Cyclobarbital is less toxic than Phenobarbital. Strange but true since cyclobarbital is more potent than phenobarbital. But potency has nothing to do with toxicity.

I figured this would be very interesting. And the data set pretty much confirmed my suspicions that vinylbital was indeed more toxic than most barbiturates according to the documentation written by Vincent Badeaux from Saint Etienne in France, a scholar who wrote a 3-piece documentation listing a diverse range of barbiturates and their general toxicities. It wasn't until I discovered a SAR program that could analyze a molecule and give a rough idea of where the toxicity of such drug would lie.

For informational purposes only. LD50/90/99 etc information would not be provided by the SAR analysis engine for legal liability reasons. Strangely enough, this data was retreived yesterday. This morning found myself unable to access the website under some strange generic message about how it "was only accessible from the campus"...well, um, LOL. LOL indeed. They must have known I was trying to scrap SAR related toxicity data and decided to "block" my access to the service. Oh, and using a VPN plus incognito tabs DID NOT work. Still blocked - meaning that whoever put the block in seriously knew what they were doing, otherwise I'd have been able to overcome it with a VPN and an incognito mode. Oh nope, no chance of access. Have NFI why they blocked this. Maybe they thought I was a "suicidal" student...well, I do have fucking Menieres disease, so I guess there's that, and oh boy does it have HIGH suicide rate, Throw in autistic spectrum disorder and you have an absolute utter fucking nightmare. So yeah, is it really that hard to blame the service for blocking a parasuicidal Menieres disease sufferer from accessing data they could use to help end their own life? I think not.

Peruse at your leisure. There is a wealth of information revealed by that SAR analysis tool. And I MEAN a wealth of information.

 

[tuppingtoncity]

What is the name of this SAR engine? Curious. On a side note there is occasionally a negative correlation between potency and toxicity as higher potency can have the affect of reducing peripheral effects in some instances as less of the drug is needed to produce the desired effect. This was an element of Shulgin’s approach to drug design

 

[Flynnal]

ADMETSar. It's a pretty good program for working out roughly how toxic something is.

Vinylbital, for one example, is supposed to be less potent than Nembutal or Seconal, and is more along the lines of Amytal combined with Seconal (aka Tuinal). That most certainly was not my experience. I thought it was a touch more potent than Nembutal from memory, as it hit quite a bit faster, and felt a lot like Tuinal (which is also more potent). Nembutal took 30 minutes to take effect. This stuff took about 20 minutes. I think from memory Seconal took only 15 minutes before I felt the effects. Tuinal was much the same. Tuinal I'd regard as VERY potent, probably because of the double-whammy effect since it's basically two barbs taken together, which would obviously have some kind of synergy. Whoever designed Tuinal designed one hell of a nasty barb combo. The hangover from Tuinal was worse than Vinylbital for sure. I "simulated" Tuinal by taking 2 x 50mg Neur-amyl tablets, and one 100mg Seconal capsule. The effect the next day left me wanting more to just feel better. The hangover was absolute hell, and I'd never felt so depressed in all my life.

However, it is more toxic than Amytal or Tuinal/Seconal, as can be seen in the figures I posted.

It is also classed as intermediate-acting, whereas Nembutal and Seconal are classed as short-acting. However, Nembutal would be much closer to Vinylbital than Seconal, which is significantly faster acting.

IMHO, Vinylbital has a very quick onset, but the duration is intermediate. I think that's where the intermediate-acting description comes from, because it hit faster than Nembutal, but not as fast as Seconal. I think both Vinyl and Nembutal are intermediate-acting, from my own experience. They are both extremely extremely extremely toxic. To be fair, they're essentially the same drug; the only thing that varies is the onset of action.

The ADMETsar works again, I just checked out methylphenobarbital, and a couple of other barbs. Also tetrabarbital too.

Methylphenobarbital:
kLog mg/L: -2.78
ATC: 38.67%

Tetrabarbital:
kLog mg/L: -2.25
ATC: 52.21%

Vinbarbital (Delvinal):
kLog mg/L: -2.32
ATC: 50.4%

Evanal (exactly like methohexital, but without the C3-N-Methyl, just your standard oxybarbiturate that has an identical side chain setup to methohexital, extremely toxic apparently; was named "Evanal Sodium", just methohexital without the N-methyl).
kLog: -2.08
ATC: 56.58%

 

[Flynnal]

And a few more to add to the list.

Thiobutabarbital:
kLog: -1.99
ATC: 58.87%

Allylisopentylbarbital: (Allyl-substituted version of Amytal)
kLog: -2.29
ATC: 51.32%

Hexethal (Ortal):
kLog: -2.69
ATC: 41.02%

Cyclopentobarbital (Cyclopal):
kLog: -2.35
ATC: 49.87%

Reposal:
kLog: -2.28
ATC: 51.53%

Spirobarbital (Wow! this one is SUPER toxic).
kLog: -1.55
ATC: 70.25%