Less addictive pain drugs may help the arthritic in future

Opioids prescribed for severe arthritis, damaged nerves and more, have also fuelled an epidemic of addiction. Evidence is growing that they’re not as good a choice for treating chronic pain as once thought. However, some fresh approaches are giving hope.

These are “bespoke” drugs, as Dr Nora Volkow, director of the National Institute on Drug Abuse, calls them. These target specific pathways and types of pain rather than acting broadly in the brain. One is Enbrel, which treats a key feature of rheumatoid arthritis, and in the process, eases pain.

Another drug in the pipeline for 17 years now is Tanezumab. It works by blocking nerve growth factor, a protein made in response to pain. Conceptualised by a small biotech company, the drug works on outlying nerves, helping to keep pain signals from muscles, skin and organs from reaching the spinal cord and brain and is good for treating arthritis and bad backs. But it hit roadblocks with suspension on testing in 2012 and 2015 due to side effects such as serious joint problems and nervous system effects in some animal studies. With two pharma giants backing it, it’s now in late-stage studies with 7,000 patients and results are expected late next year.

Researchers have also been drawn to the idea of a drug that could keep people from needing long-term pain relief in the first place. A California-based biotech firm is testing a novel, long-acting version of two drugs — the anesthetic bupivacaine and the anti-inflammatory meloxicam — for notoriously painful operations like tummy tucks, bunion removal and hernia repair. Company studies suggest it can numb wounds for about three days and cut patients’ need for opioids by 30 to 50 per cent.

There’s a good chance of preventing brain responses that lead to chronic pain if patients can get through that “initially very rough period,” said Dr Harold Minkowitz, a Houston anesthesiologist. Studies so far though are mid-stage — too small to prove safety and effectiveness.

Some companies have their eyes on sodium channel blockers, which affect how nerves talk to each other. Others are testing cell therapies for nerve pain. Stem cells can modulate immune responses and inflammation, and may “overcome a raft of problems,” said an independent expert Dr Jianguo Cheng, a Cleveland Clinic pain specialist and science chief for the American Academy of Pain Medicine. It’s a long way to go, but then, research has come a long way, too, say experts.

Opioid addiction

Drugs like Vicodin, OxyContin work powerfully in brain areas that control pleasure and pain, but the body adapts to them quickly, so people need higher and higher doses to get relief
In the US, every day, an overdose of prescription opioids or heroin kills 91 people, and legions more are brought back from the brink of death