Resiniferatoxin is a hot topic among those looking for opioid alternatives. How hot? It scores 16 billion units on the Scoville scale that measures the hotness of peppers and spicy food. That makes resiniferatoxin, also known as RTX, 10,000 times hotter than the hottest known pepper, the Carolina reaper.
RTX, which is found in a flowering cactus-like plant native to Morocco known as Euphorbia resinifera or resin spurge, is not only fiery, it's accurate. It can target and destroy nerve endings for pain, and for pain only.
Unlike opiates, the chemical only attaches to a pain-sensing molecule called TRPV1. This means, if you have a pain in your toe, RTX wouldn't numb your entire foot.
“RTX directly interacts with afferent nerve cells without affecting sensations such as touch, pressure, acute prickling pain, vibration sense or muscle coordination function. RTX can potentially help patients with terminal cancer pain, after a single epidural injection,” according to Sorrento Therapeutics, which has an RTX drug in clinical trials.
When tested on dogs, pain subsided for an average of five months. The National Institutes of Health is conducting trials on bone cancer patients with RTX as a painkiller.
“For many of the cancer patients, we need to have the drug remove pain from a lot of different regions. So we give it into a compartment where the nerves to the lower half of the body are gathered together,” the NIH's Michael Iadarola told Wired.