Enteral( internal) administration of medicinal substances

The most common, at the same time, relatively simple and convenient way of introducing medicinal substances is to take them inside. Advantages of this path are comparative safety and absence of complications typical for parenteral administration. Drugs administered enterally can have both local( some antimicrobial and anthelmintic agents) and systemic effects.

1. Ingestion by mouth - orally .In the treatment of diseases of internal organs, oral administration should be made of medications that are well absorbed by the mucous membrane of the stomach or intestine. When treating digestive organs, a high concentration of the drug must be created in the gastrointestinal tract. In this case, on the contrary, drugs that are poorly absorbed are used, which makes it possible to obtain a good local effect in the absence of side systemic reactions. In severe cases of certain diseases, it is desirable that the concentration of the drug be high locally( for example, in the lumen of the intestine) and in the blood.

Inside medicinal substances are administered in the form of solutions, powders, tablets, capsules, pills. To prevent the irritating effect of certain drugs on the gastric mucosa, tablets coated with a coating soluble in the alkaline environment of the intestine are used. There are dosage forms( tablets with multilayered membranes, etc.), providing a gradual, long-term release of the active principle, thus allowing the therapeutic effect of the drug to be prolonged. Some tablets and capsules obtained by patients lying down, can linger in the esophagus and cause its ulceration. To prevent this complication, tablets and capsules should be washed down with plenty of water.

2. Introduction to the language - sublingually. Mucous membrane of the oral cavity has abundant blood supply, which facilitates rapid absorption of the substance, ingress into the systemic bloodstream. With sublingual administration, the drug is not exposed to gastrointestinal juice and enters the systemic bloodstream through the veins of the esophagus, bypassing the liver, which avoids its biotransformation. The drug should be kept under the tongue until complete resorption. Swallowing it with saliva reduces the benefits of the drug. With frequent sublingual use of drugs, irritation of the oral mucosa may occur.

3. Introduction to the rectum - rectally .The rectum has a dense network of blood and lymphatic vessels. Many medicinal substances are well absorbed from the surface of its mucous membrane. Substances that are absorbed in the lower part of the rectum, through the lower hemorrhoidal veins, enter the systemic circulation, bypassing the liver. Rectal administration of the drugs allows avoiding gastric irritation.

Disadvantages of oral use of medicines when it is necessary to receive and systemic effect are as follows:

• relatively slow development of the therapeutic effect;

• large individual differences in speed and completeness of suction;

• the effect of food, the state of the gastrointestinal tract, drugs on absorption;

• impossibility to use medicinal substances that are poorly absorbed by the mucous membrane or destroyed in the lumen of the stomach and intestines, when passing through the liver or exerting a strong irritant effect;

• inability to administer drugs through the mouth during vomiting and unconsciousness of the patient.

In this way, medicines can be used in cases where peros is difficult or impractical( nausea, vomiting, spasm or obstruction of the esophagus are noted).The shortcomings of this path include pronounced individual fluctuations in the speed and completeness of absorption of drugs, psychological difficulties and inconveniences of use. Rectally injected suppositories( suppositories) and fluid with enemas. This route of administration is used both to obtain local( for example, ulcerative colitis) and systemic effects.