Analgesic activity is manifested by substances having a different chemical structure and is realized by various mechanisms. Modern analgesics are divided into two main groups: narcotic and non-narcotic. Narcotic analgesics, providing, as a rule, a strong analgesic effect, cause side effects, the main one of which is the development of addiction. Non-narcotic analgesics are less effective than narcotic ones but do not cause any addiction.
Opioids, in particular, Tramadol and others, which can be bought in online pharmacies, are characterized by strong analgesic activity, which makes it possible to use them as highly effective painkillers in various fields of medicine, especially in traumas, surgical interventions, wounds, etc. And in diseases accompanied by severe pain syndrome (malignant neoplasms, myocardial infarction, etc.). By exerting a special influence on the central nervous system, opioids cause euphoria, a change in the emotional color of pain and reaction to it. The most significant disadvantage is the development of mental and physical addiction.
Most synthetic drugs are obtained by the principle of modifying a molecule of morphine with the preservation of elements of its structure or its simplification.
Due to the severity of the analgesic effect and the side effects, the preparations differ from each other, which are due to the peculiarities of their chemical structure and physicochemical properties and, accordingly, to the interaction with the receptors involved in the realization of their pharmacological effects.
In the understanding of the neurochemical mechanisms of the action of opioids, an important role was played by the discovery in the 1970s of specific opiate receptors and their endogenous peptide ligands, encephalin, and endorphins. Opiate receptors are concentrated mainly in the central nervous system but are also contained in peripheral organs and tissues. In the brain, opiate receptors are mainly in structures that are directly related to the transmission and coding of pain signals.
By the nature of interaction with opiate receptors, Tramadol is classed as agonists (all types of receptors are activated).
In the mechanism of action of opioids, the depressing effect on thalamic centers of pain sensitivity plays a role, carrying painful impulses to the cerebral cortex.
A number of opioids are used in medical practice. In addition to morphine, its prolonged dosage forms have been developed. A significant amount of synthetic highly active analgesics of this group, which have a high analgesic activity with different degrees of “drug addiction potential” (the ability to cause a painful addiction), has also been obtained.
Side effects of different narcotic analgesics are approximately the same, although some patients tolerate some drugs better than others, used in equivalent doses.
The effect on the central nervous system is manifested by sedation, euphoria, and narrowing of the pupils.
Respiratory depression depends on the dose and is especially pronounced with an IV injection. Opioids should be used with caution and in smaller doses in patients with impaired breathing function.
The effect on the cardiovascular system is manifested by peripheral vasodilation and arterial hypotension, especially with intravenous administration.
The most frequent manifestation of side effects on the gastrointestinal tract is constipation. Patients receiving narcotic analgesics should be prescribed softening laxatives. Patients with inflammatory bowel diseases may develop toxic megacolon. Nausea and vomiting are alleviated when lying down.
Narcotic analgesics increase the tone of the bladder, ureters, and sphincters of the urinary tract, which sometimes leads to a delay in urine.
Allergic reactions – urticaria, rashes, anaphylaxis – are infrequent.