Hitler believed that one of the causes for Germany's loss in WW1 was the Jewish people (If I remember correctly ). When he met with other German Officials they found the final solution to the Jewish problem. The concentration and extermination camps punished the Jewish people, and was a way to mass kill them quickly. Also, I doubt (though I'm not sure...lol) that there would have or even could have been a pill that could do that. The US and Russia were ahead of the other countries, and the US didn't even start finding ways to treat cancer, polio, and many other diseases until the 1950s, so I doubt that it'd have been possible for Germany to make this pill.
But hey, what do I know. I could be completely wrong on all my facts.