Hot Topic: RTX
Written by Editor   
Tuesday, December 11, 2018 11:54 AM

Resiniferatoxin (RTX) 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 RTX 10,000 times hotter than the hottest known pepper, the Carolina reaper. 

Found in a species of the spurge flowering plants native to Morocco known as Euphorbia resinifera or resin spurge.  It occurs on the slopes of the Atlas Mountains.  RTX 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 other sensations such as touch, pressure. It is currently the most potent TRPV1 agonist known.  The dried latex of the plant has been used as ancient medicine since at least its first written record from the time of Roman Emperor Augustus.

RTX is a capsaicin analog tested as an analgesic since 1997.  The plant contains a milky fluid or latex, which in its dried form is called Euphorbium. Capsaicin, the primary vanilloid compound found in hot peppers can interact with a vanilloidreceptor on primary sensory neurons mediating pain (nociception) and neurogenic inflammation such as neuropathic pain, as in diabetic polyneuropathy and postherpetic neuralgia. RTX injected subcutaneously into a rat hind paw several minutes before a surgical incision reduced postsurgical pain for 10 days in a NIH study published March 2018.It is tested to treat pain with advanced cancer.

RTX has a score of 16 billion Scoville heat units, making pure resiniferatoxin about 500 to 1000 times hotter than pure capsaicin.  RTX is toxic and can inflict a chemical burn in microscopic quantities. The primary action of resiniferatoxin is to activate sensory neurons responsible for the perception of pain.  Animal experiments suggest that, in humans, ingestion of 10 g may be fatal or cause serious damage to health.  It causes severe burning pain in sub-microgram (less than 1/1,000,000th of a gram) quantities when ingested orally.

Currently, Sorrento Therapeutics has been developing RTX as a means to provide pain relief for forms of advanced cancer.