Opioids are painkillers that are used to treat long-term and severe pain. Opioids belong to a group of substances that act on opioid receptors (pain receptors). Thanks to opioid painkillers, even the strongest pain can be relieved, in most cases making it imperceptible to the patient.
Opioids and their action
Opioids act on opioid receptors in the human body by stopping pain impulses from reaching them. Opioid receptors have been known since the 70s. They are located in the central and peripheral nervous systems. Typically, opioids act on opioid receptors such that when a drug molecule is attached to them, hyperpolarization occurs, in which the excitability of the receptor’s nerve cells is reduced, so that they become less sensitive or not at all sensitive to pain stimuli. Some opioids have the effect of reducing the re-uptake of certain neurotransmitters in the nervous system. Some opioid drugs bind to a specific receptor, others affect all types of opioid receptors (there are three of them). Some opioids are pure opioid antagonists (that is, stimulate them), while others excite some receptors and inhibit others. Opioids have been known in medicine for a long time. From time immemorial, natural opiates, mainly obtained from opium poppy seeds, have been used to relieve pain. Morphine, a strong opioid relieving pain, has been known since the XNUMXth century.
Opioids are used in severe pain that lasts for a long time. Pain severity is measured according to a three-step so-called analgesic ladder.
The first line of pain relievers and non-steroidal inflammatory drugs are in the first step of this pain scale. They are sufficient for mild pain relief. The second and third steps of the analgesic ladder are opioid drugs – weaker in the second and stronger in the third. The most common cases when opioid analgesics are used, including those from the third step of the analgesic ladder, are neoplastic diseases accompanied by severe pain and conditions after major surgery. Opioids are also used in the case of a heart attack, pulmonary edema, and conditions associated with extensive trauma, such as burns. Other uses of opioid drugs include, for example, patient preparation (premedication) for surgery, treatment of heroin dependence, and the treatment of persistent diarrhea. In the latter ailment, an opioid drug called loperamide (Imodium Instant, Stoperan) is used, which does not affect the central nervous system, but only opioid receptors in the gastrointestinal walls.
Types of opioid analgesics
There are several ways to break down opioid pain medications. One is the distinction between natural and synthetic opioids. Natural opioids include, for example, morphine and codeine, and endorphins, also known as endogenous opioids, because they are produced naturally by the human body. Synthetic opioid painkillers include, for example, fentanyl, pethidine, and methadone. Another division is the distinction between weak and strong opioids. The former include tramadol, codeine and hydroxycodeine. The latter are morphine, fentanyl, buprenorphine and oxycodone.
Check also other drugs whose active ingredient is morphine
Opioid analgesics can be administered in the form of tablets, patches applied to the skin (usually working for 72 hours), syrups, nasal sprays and solutions for intravenous administration via a drip.
Initially, the opioid dose is as low as possible, and the amount is increased as needed if lower doses do not work. Opioid analgesics should be administered at fixed times, but an additional dose may be given as needed, provided pain relief is not achieved.
Taking opioid analgesics during pregnancy is strongly contraindicated, but there are cases when it is necessary. Then the doctor individually assesses whether the possible benefits of administering the drug outweigh the risk of harm to the fetus.
The use of opioid analgesics can lead to a number of side effects. The most serious problem is that they are easy to get addicted to. In order to monitor addicts, it is worth performing a Shipping test for the presence of psychoactive substances – a semi-quantitative determination that can be used, for example, for control at the workplace.