Analysis: our ancestors prayed for relief from pain, but we rely on a huge range of drugs and opioids to get rid of that 'ouch' feeling

From toothache to scraped knees and migraines, pain is a universal human experience. Our everyday life is entangled with pain and its alleviation. But how we understand pain in the 21st century is considerably different to our ancestors from the 18th and 19th centuries.

Back then, many people considered pain as a message from gods or nature that could purify their soul and let them be free from the chains of their sin. Many readers will be familiar with the expression, "suffer in this life and you will not suffer in the next one". Historically, pain has been seen as part of God's will. As a result, many people tolerated pain and prayed for relief.

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This is in extreme contrast to our modern-day relationship with pain. Over the last 100 years, we have engaged in the restless pursuit of pain elimination through the fastest and most effective way possible and this is where medicine and painkillers have come into their own.

Pain is a type of perception, like tasting, smelling and hearing. However, those senses inform you what is going on in the outside world, but pain tells you what is going on within the world of your own body. Imagine that you have a broken bone. Nerve cells around the bone pick up the signal that something is wrong. The nerve network relays this message to the spinal cord. From there, it shoots up to the brain. The brain then translates the message and registers the feeling: ouch!

Sometimes these messages can be overbearing and medical practitioners use painkillers to help those in need. Painkillers work with different biological mechanisms, some of them stop swelling in the tissues while others interfere with the pain centre in the brain and increase the pain threshold of the body. Depending on these mechanisms, painkillers are generally classified in two categories: non-steroidal anti-inflammatory drugs and weak or strong opioids.

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Today, we rely on purified and controlled versions of both painkillers, but both types have been helping relieve pain for thousands of years. Non-steroidal anti-inflammatory drugs are mainly prescribed in low doses to treat a range of conditions such as relieving pain, reducing inflammation (redness, heat and swelling) and bringing down a fever. This group has been around for thousands of years with the Greek physician Hippocrates claiming that willow leaves and bark relieved pain and fever. The painkilling compound at play was salicylate, a precursor to modern day aspirin. Other known painkillers in this group include ibuprofen, diclofenac and naproxen.

These are the most common pain relief drugs in the world, but their range of use is expanding beyond just the pain threshold. According to a 2006 study from the Centres for Disease Control and Prevention, four out of five Americans with heart disease use aspirin to regulate their condition. Moreover, current research into these drugs is investigating the possibility that they can prevent breast cancer in older women.

They have been considered for the treatment and prevention of Alzheimer's disease (AD) for more than two decades. Biochemical markers in the brain of individuals with AD suggest that inflammation might be a driving cause of the disease, something that these drugs typically treat. However, it should be noted that the above applications are still being examined by researchers and these types of applications are not yet used in medical practice. When taking any of these painkillers, you should seek medical advice and always read the labels.

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The second category of pain killer is weak and strong opioids. Similar to non-steroidal anti-inflammatory drugs, they have been around for thousands of years. Derived from the poppy, the most active compound in opium, morphine, is named after Morpheus, the Greek God of dreams.

Opioids are still successfully used in medicine today with strong opioids like morphine, oxycodone, pethidine and tramadol and weak opioids such as codeine and dihydrocodeine used to treat severe pain. Opioids function by attaching themselves to receptors in the brain. Once secure, they interfere with the brains ability to recognise pain. They can also slow down a patient’s breathing rate and have a calming and anti-depressing effect.

Opioids may be a powerful painkiller, but their downside is that they are highly addictive and have adverse impacts on the body’s regulation of the liver and kidneys. In light of this, they are regulated in many countries. In the US and the UK, this happened at the beginning of the 20th century, with the Dangerous Drugs Act in the UK (1920) and the Harrison Narcotics Tax Act in the United States (1914). Yet this has not stopped the rapid increase in domestic opioid use in America, with many commentators referring to the last 20 years as an "opioid epidemic". The same advice applies to those who need to take strong and weak opioids: consult with a medical practitioner and always read the label.

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The two categories of painkiller outlined above are the typical tools used by medical practitioners to manage pain. But these options are expanding and becoming more refined all the time in efforts deliver pain killers that are faster and more efficient.

Ireland has a strong presence in this developing space. Research into novel and improved forms of painkiller is a hot topic within the scientific community. Researchers in SSPC, hosted by the Bernal Institute in the University of Limerick, are working on developing new techniques and strategies to improve painkillers with higher efficacy and lower side effects. These efforts are performed in close collaboration with industrial partners and they will impact patients’ quality of life.

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READ: The complex world of pain

As an example, the team that I work with have studied the effect of adding a type of vitamin B3 to ibuprofen to increase its bioavailability in the body and enhance its effect as a painkiller. We successfully improved the dissolution rate (speed at which something dissolves) of ibuprofen in the gastrointestinal tract by a factor of three through the addition of the specific form of vitamin B3. In the future, it is hoped that the research can be used as a platform for combining multiple drugs with different therapeutic effects in the same tablet. With regard to painkillers, the future promises to be more pain free than ever before.

The views expressed here are those of the author and do not represent or reflect the views of RTÉ