Most drugs of abuse are, or were at some point, used as medicine. The ones you mention courage2 have for the most part been surpassed by safer medications but all three can still be legally prescribed in many countries. Off the top of my head methamphetamine is used as a weightloss drug, cocaine as a topical anesthetic and heroin (under its medical moniker of Diamorphine) is used as a very strong painkiller.
Oddly enough, the one that's legal almost everywhere (and that happens to be my kryptonite) good old ethanol has very few medical benefits besides making a pretty decent mouthwash and hand sanitiser and is not used medically at all, save as an antidote to the poison found in antifreeze if nothing else is available. Yes Walking Dead fans, that's a real thing apparently!
Diamorphine I especially appreciate as a medical drug as it is heavily used in the UK in palliative care. Used in the this manner it is truly invaluable in my opinion, and I will always be grateful that it was available to help my family members who have passed from terminal cancer move on to the next world with dignity and without pain or fear.
Last edited by Madnellie; 10-06-2018 at 11:49 PM.
Reason: Bit of a wall of text