Thiopental, pentobarbital, propofol, all three very powerful sedatives. In high doses, they completely shut down consciousness and stop breathing. All three are the gold standard for euthanasia. Although thiopental is an ultra-short-acting anesthetic, it is not easily metabolized. Therefore, it is not used in the maintenance of anesthesia. A rapid injection of 1.5 - 2 grams of thiopental is fatal for the average person. 10 grams of thiopental by oral administration should be fatal. This is my personal opinion.