Should there be one? Pain is a symptom of something else, treat the root cause. Managing pain should only be a temporary measure.
"The team bred genetically engineered mice from embryos that had HCN2 excised from their DNA. Subsequent experiments showed that these mice did not develop neuropathic pain (the kind that affects the nervous system and is often caused by long-term conditions such as cancer or diabetes). Not only that, the mice with HCN2 cut out were still able to feel acute pain – the necessary, protective jolt that tells us to remove our finger from a drawing pin. “That’s the holy grail,” McNaughton told me"