Medicinal substances can realize their effect on the body in several ways. It depends on a number of concomitant factors: route of administration, place of application, duration of use and specificity of the compound itself.
Resorptive action
One of the ways that substances affect the body is resorptive (from lat. Resorbeo - "absorption"). This is the effect that manifests itself after absorption of one or another compound in the blood. Once in the vascular bed, such a substance can spread throughout the body in a short time and have the desired effect on a specific target organ (selective effect), tissue or the body as a whole (general effect).
The resorptive effect is characteristic not only of drugs, but also of many toxic substances. This effect underlies many pesticides, such as those used to kill insects. The resorptivity of a compound depends on the penetration pathway and its ability to penetrate cell barriers. The resorptive effect can be either depressing or exciting, it all depends on the specifics of the drug.
Penetration into the body
A resorptive agent can enter the bloodstream in various ways: directly by injection, through the gastrointestinal tract after absorption in the intestine, or by absorption through the skin. In the latter case, a skin-resorptive effect occurs. This is due to the properties of certain substances penetrate the body cover. This effect has drugs in the form of ointments, creams, lotions, compresses, rinses.
If the action of a substance is carried out only in the place of its direct application, then it is called local. The zone of its influence is strictly localized. However, this concept wanders relative, because the penetration of a substance through the skin into the general bloodstream occurs in any case. Therefore, in some situations, local action can be called resorptive.
Method of exposure
The resorptive effect of drugs can be direct or reflex:
- Direct influence. It is realized only in the place of direct contact of a substance with a tissue or organ.
- Reflex effect. It is implemented in a slightly different way. The drug substance first affects certain receptors, causing their irritation. Further, the effect is manifested in a change in the general condition or in the nerve centers involved in the work. In some cases, the work of those organs whose receptors are irritated changes. For example, with a disease of the respiratory system, the use of mustard plasters is used. At the same time, by exerting influence on the exteroreceptors of the skin, metabolic processes in the lung tissues are reflexively increased, and the respiratory rate increases.
Resorptive drugs
There are various groups of resorptive drugs depending on their mechanism of action. Some of them:
- Means for separating sputum when coughing. First, they are absorbed in the intestine, then, getting into the bloodstream, reach the respiratory system (lungs, bronchi). After that, the active release of the active substance (sodium iodide, ammonium chloride) by the mucous membranes of the lungs and bronchi begins . This phenomenon determines the healing effect - liquefaction of sputum, its excretion.
- Local anesthetics (lidocaine, novocaine). The mechanism of their action is associated with blocking the transmission of a nerve impulse, due to which certain parts of the body lose tactile, thermal or other sensitivity.
- Narcotic analgesics (morphine, codeine). Their action is associated with the blocking of nerve impulses entering directly into the brain, which eliminates or weakens the pain syndrome.