There is a pain beyond pain. Most of us won't have to experience it in our lives, but the sort of superpain known as neuropathic pain is hardly rare. Neuropathic pain is a feature of a number of diseases, including diabetes, multiple sclerosis, cancer, and HIV. Unlike typical acute pain caused by an injury or wound, neuropathic pain comes from a patient's own nervous system. There is no wound to heal, only pain lasting more or less forever.
Because what we're dealing with is effectively "mind pain," it follows that treating it is far more difficult than conventional pain, if not just impossible. In fact, only one-in-three patients sees relief at all from the wide field of current treatments, from antidepressants to opioids to pot. Even with surgery performed on actual nervous system tissue—literally sealing off pain's pathways—relief is fleeting.
Opioids, like morphine, are the most consistently effective form of treatment for neuropathic pain. But by now we're all pretty well aware of the dire risks of the drug and its siblings: addiction, overdose, abuse. But, as far as helping people dealing with this extreme category of pain, there's nothing else like it. Or is there? Enter the common cone snail, whose venom may function as a pain reliever 100 times as powerful as morphine, according to research presented today at the 247th National Meeting & Exposition of the American Chemical Society.
The snail venom contains small proteins called conotoxins, a potent class of neurotoxins whose exact mechanisms of toxicity are as yet poorly understood. However, their analgesic properties have already been noted, and so far one drug currently exists on the market based on conotoxins. The catch is that that drug, ziconotide, needs to be injected directly into the lower spinal cord, which, obviously, isn't a day-to-day option.
The new research, led by the University of Queensland's David Craik, is the first to demonstrate an oral version of conotoxin therapy. Though its effects have only been observed in lab rats, Craik and his team theorize that conotoxin drugs would have less side effects and less potential for addiction and abuse, while boasting pain relief orders of magnitude above current drugs.
"We don't know about side effects yet, as it hasn't been tested in humans. But we think it would be safe," Craik said in a press release. "It acts by a completely different mechanism than morphine so we think it has a minimal possibility of producing the side effects of that medication. That is one of the big advantages of this drug." The research team is currently applying for funding to expand their testing to humans