What Does Science Say About Opioids?

An opioid is not the same thing as an opiate. Although popular thinking believes that opioids are just external addictive drugs, this is not entirely correct.

Opioids have been used for thousands of years as pain relievers. For at least six thousand years, mankind has known its analgesic properties. Later, in the year 1086, the substance we know as morphine could be chemically isolated.

Science has progressively discovered that  humans have internal systems to interact with opioids. These receptors spread throughout the body are there for physiological reasons. Thus, we must distinguish between two concepts:

• Opioids: This term is used for all substances, whatever their origin, that can bind to an opioid receptor in the body.

• Opiates: are substances derived from opium that have an opioid action. They are not found naturally in humans. This is the case with morphine, for example.

All opiates are opioids, but the opposite is not true. Some opioid substances that circulate in the blood, such as endorphins, are natural and not derived from opium; therefore, they are not opiates.

We also have a subdivision between opiates, distinguishing their natural or synthetic origin. There are opiates that come directly from the opium plant and others that are manufactured artificially. Both the pharmaceutical industry and the world of engineered drugs develop these synthetic products.

Endogenous opioids

There is a group of opioids that do not come from outside the body, but are intrinsic. In other words, they  are substances that the human body manufactures and that intervene in various natural processes in the organs.

These endogenous opioids, as they are called, were discovered by scientists John Hughes and Hans Kosterlitz in 1975. Three groups were identified:

• Endorphins.
• Enkephalins.
• Dinorphins.

Endogenous opioids have a variety of functions, from pain analgesia to mediating stress responses.  They have also been linked to cardiac function and the immune system’s response to infections.

The body is able to store endogenous opioids for use when needed. On the other hand, there are   endogenous cannabinoids , which are substances manufactured when they are needed and which are not stored.

How do opioids relieve pain?

One of the great characteristics of opioids is that they are pain relievers. They relieve pain very efficiently and many of them have no action limit, which is why they are used in chronic painful pathologies.

Endogenous opioids are also analgesics. That’s why,  when we secrete more endorphins because we’re going through a state of happiness, our pains calm down. The same is true for people with osteoarthritis, who suffer less from increased endorphins when playing a sport they enjoy.

According to their analgesic action and to which receptors in the central nervous system they bind, drug opiates are classified into:

• Pure agonists:  are those that act on some receptors identified with the  Greek letter μ . They are strong analgesics and cause euphoria. In this group is morphine.

• Agonist-antagonists: drugs such as nalbuphine make up this group.
• Partial agonists: buprenorphine is the prime example.
• Pure Antagonists: These drugs are capable of reversing the effect of other opiates. They are used ​​in case you have to treat a morphine poisoning. We can mention naltrexone and naloxone.

Adverse effects

As with any substance, natural or artificial, excess is the cause of intoxication and adverse effects. Opioids are not exempt from this.

Adverse effects usually appear with opioids used ​​such as medications or recreational drugs. Endogenous opioids do not generate these undesirable reactions because the body regulates them.

Among the adverse effects of opioids, we can mention:

• Digestive disorders:  mainly constipation, as opioids tend to reduce the peristaltic movements of the digestive tract. There may also be nausea and vomiting.
• Dizziness and drowsiness.
• Headache.
• Sweating.
• Respiratory depression: A much feared effect of opiates is the possibility of depressing breathing, causing death. Therefore, the administration dose must be supervised.
• Addiction: opiates are addictive, both those used as painkillers and recreational drugs. The addicted individual experiences the urgent need to consume them and requires more and more doses to achieve the same effect. This is a serious social problem that requires approaches from different perspectives, not just the medical aspect.

Conclusion

Opioids are known for their powerful analgesic action. In fact, thanks to their ability to treat pain, they are used for various ailments. However, their use should be done with caution, as they tend to become addictive when used as medication. There are even those who use them as recreational drugs.