Veterinary Question - Pentobarbital

If you look up the MSDS (Material Safety Data Sheet) for it, it gives the LD50 as ~120 mg/kg body mass. That means that half of a group of rats died from an oral dose of 120 mg per kg of mass. Which, if we assume that can be extrapolated to humans, means a dose of ~12g for a 220 lb person would have a 50:50 chance of killing him. That's probably about 10-12 mL, depending on the density.

You may want to search under Sodium pentobarbital. It comes in liquid form in bulk (for SPCA and other euthanasia use, for example) and is VERY tightly controlled by gawd knows how many layers, branches, and divisions of cops and bureaucrats.

For putting down a horse, you use Sodium Pentobarbital administered by two doses of 60ccs for a total of 120ccs for a 1000 pound horse. My guess is half the dose would be more than enough for a 200 pound person. If you properly planned, you would be able to administer both doses to yourself, if you wanted to be sure (there's a measurable amount of time between administration and effect, but not much).

Death is rather sudden. With a horse, which will be standing, it will crash to the ground. The drug kicks in very quickly and the process appears painless.

Unless the victim was unable to respond, it would be rather hard to administer. You do have to find a vein to insert the needle. (Horses don't have much of a problem with needles.)

Very heavily regulated. Unless you stole it, you can't get it. I believe that air transport of horses still use a humane killer (basically a gun) as horses in the air that have problems have to be put down quickly. I don't believe that they're allowed Sodium Pentobarbital, unless a vet is traveling with the horse (unlikely).

Best of luck,

Jim Clark-Dawe

The fatal dose in a non-addicted adult is 3-6 grams injected all at once or over a short period of time. It's rapidly absorbed, so you've got 15-30 min between administration and effect.