The Nine Lives of Hydroxychloroquine
Martin J. Bergman, MD
May 11, 2015
https://rheumnow.com/blog/nine-lives-hydroxychloroquine

[snip]

The HCQ story begins in 1638 when the wife of the Viceroy of Peru, Countess Cinchona, acquired malaria while living in the New World. Rather than getting the “approved” therapy, blood-letting, she was treated by an Incan herbalist with the bark of a tree (eventually, named for the countess-Cinchona Tree). Her response was dramatic; when the Viceroy returned to Spain, he brought with him large supplies of the powder for general use, which at the time was controlled by the Church and was thus called “Jesuit’s Powder”.

It took nearly two centuries for the active substance, Quinine, to be isolated from the bark (and was eventually to make a name for itself as a tonic to be added to gin).

Over the next century, quinine would become a common component in folk medicines and patent remedies for the treatment of malaria in the southern states of America, as well as for generic malaise. By the 1940s, quinine, or rather its derivative chloroquine, was recognized for its anti-malarial properties and found use among troops fighting in the Pacific during WW-II. However, it was noted that this compound had significant toxicities. In 1945, a modification of this compound via hydroxylation led to the development of HCQ, which was found to be less toxic and remains in use, without change, to this day.