Medicinal substances can realize their effect on the body in several ways. It depends on a number of related factors: the route of administration, the place of application, the duration of application and the specifics of the compound itself.
Resorptive action
One of the ways substances influence the body is resorptive (from lat. resorbeo - "absorption"). This is the effect that manifests itself after the absorption of a particular compound into the blood. Once in the vascular bed, such a substance is able to spread throughout the body in a short time and have the desired effect on a specific target organ (selective action), tissue or the body as a whole (general action).
Resorptive action 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 pathways of entry and its ability to penetrate cell barriers. The resorptive effect can be both depressing and exciting, it all depends on the specifics of the drug.
Penetration into the body
A resorptive agent can enter the blood in various ways: directly by injection, through the gastrointestinal tract after absorption in the intestines, or by absorption through the skin. In the latter case, a skin-resorptive effect occurs. This is due to the properties of certain substances to penetrate the skin of the body. Medicines in the form of ointments, creams, lotions, compresses, rinses have this effect.
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, which is why the penetration of a substance through the skin into the general bloodstream occurs in any case. Therefore, in some situations, the local action can be called resorptive.
Method of influence
The resorptive action of medicinal substances 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 influence. It is implemented in a slightly different way. The drug first affects certain receptors, causing them to become irritated. Further, the effect manifests itself in a change in the general state orinvolved in the work of the nerve centers. In some cases, the work of those organs whose receptors have been irritated changes. For example, with a disease of the respiratory system, the imposition of mustard plasters is used. At the same time, by influencing the exteroreceptors of the skin, there is a reflex increase in metabolic processes in the tissues of the lungs, and the intensity of respiration increases.
Resorptive drugs
There are different 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 intestines, then, getting into the bloodstream, they reach the respiratory organs (lungs, bronchi). After that, active secretion 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 blocking nerve impulses that go directly to the brain, which eliminates or reduces pain.
