Sublime

This phenomenon, widely observed and verified by animal studies, has come to be called opioid-induced hyperalgesia. Algesia, from the Greek word algesis, means sensitivity to pain. What’s more, when these patients tapered off opioids, many of them experienced improvements in pain.

The opioid receptor blocker naltrexone is currently being explored as a medical treatment for chronic pain. The idea is that by blocking the effects of opioids, including the ones we make (endorphins), we trick our bodies into making more opioids as an adaptive response.

In 1874, English researcher Charles Wright first synthesized heroin by boiling morphine. People quickly embraced this potent, fast-acting drug. Opioid use wasn’t regulated, and by the end of the century hypodermic syringe sets for personal use were sold in the Sears, Roebuck and Co. catalog.