Thousands of years after humans discovered the pain-relieving effects of resin from opium poppies, clinicians still rely in opioids to treat severe pain, which reduce the intensity of pain signals reaching the brain. Medications that fall within this class include hydrocodone (Vicodin), oxycodone (OxyContin, Percocet) and morphine (Kadian) and codeine. ‘Opiods still work best for people suffering from injury or disease like cancer and there are variations of the opioid molecule which can be used in different circumstances,’ says Professor Steve Bazire, Honorary Professor, School of Pharmacy, University of East Anglia, Norwich. Codeine is used for milder pain while morphine is used to take away the pain after surgery.
‘Sadly, in terms of available medications, the cupboard is rather bare. Opioids have obvious drawbacks,’ explains Dr Roger Knaggs, an Advanced Pharmacy Practitioner – Pain Management at Nottingham University Hospitals NHS Trust. ‘Not least is that they are addictive and their effects wear off over time. They also have many side effects including constipation and drowsiness.
Unfortunately there are very few other pain-relieving molecules in development. ‘A newer molecule, buprenorphine, which is less addictive because its effects taper off at higher doses, is now sometimes given as a long-lasting implant in the base of the spine,’ says Professor Bazire.
However, there are some completely new classes of pain drugs on the horizon. Resiniferatoxin, (RTX) is an experimental compound derived from the resin of a spiny cactus-like plant called Euphorbia resinifera. Studies have shown that the active ingredient of this resin binds to a receptor found on the surface of heat-pain sensing neurons. This prompts an influx of calcium ions to pour into the cell, killing it.
Another plant extract from the bark of the French maritime pine tree, Pycnogenol, has been found to have natural inflammatory properties. Its ability to reduce joint pain in arthritis sufferers by 55 per cent was reported in the journal of Phytotherapy Research in 2008 and since then it has been widely sold as a supplement. Pycnogenol contains chain-like structures similar to those found in green tea.
A US study published in the July 2013 issue of the Annals of Neurology reported that a derivative of docosahexaenoic acid (DHA), the main ingredient of fish oil supplements, can reduce and even prevent pain caused by injuries to the sensory system. Researchers at Duke University found that a bioactive lipid, which is also present in human white blood cells, helped to reduce brain inflammation.
And a high-pressure oxygen therapy used to treat burn victims, also seems to help women suffering from fibromyalgia, according to an Israeli study published in Plos ONE in July 2015. Researchers at Tel Aviv University looked at 60 women who suffered from the condition and found that 70 per cent of women who underwent the therapy for a two months period, had significant improvement of their symptoms which included musculoskeletal pain, fatigue, memory loss and mood swings.
Devices like TENS machines can offer some relief and others say that acupuncture is helpful. Or short acute pain, aspirin and ibuprofen are very effective and often overlooked, according to Professor Bazire.