In 1851, the first subcutaneous injection of a dosage form was performed by a Russian doctor from a military hospital in Vladikavkaz. For injection, a liquid solution was used. Since there were no syringes as we used to see them today, he used a fragment of a barometric tube with a piston. A silver tip was attached to the free end, resembling a needle in shape. A year later, a syringe was developed for the injection, developed by a doctor from the Czech Republic - Pravets.
Definition, benefits of choice
By definition, dosage forms for injections are understood to mean powder and aqueous sterile, oil solutions, emulsions and suspensions, tablets that must be previously dissolved. They are introduced into the body using a syringe, violating the integrity of the skin. If the volume of the solution is very large (more than 100 ml), the medicine is administered by infusion, by the infusion method.
The main advantages of using liquid dosage forms for injection:
- Instant action (the effect occurs immediately as the solution penetrates the body).
- Dosage forms for injection do not affect the gastrointestinal tract, liver, and do not violate the pharmacological effect of other drugs (hormones, antibiotics, insulin).
- You can enter the remedy for a person who is in an unconscious state.
- The medicine in most cases is not felt either in taste or in smell.
Disadvantages of use
Many people remember the discomfort when they had to do injections. Any damage to the skin causes pain. This is the main reason for refusing treatment by injection. Do not exclude the risk of infection in the circulatory system, the formation of hematomas, bumps. It is important to resort to this method of administering the dosage form in a specialized medical institution. This is a fully justified requirement, since one of the undesirable consequences is the ingress of air bubbles or particulate matter into the body, the risk of contracting HIV and hepatitis.
With the introduction of certain medicinal solutions for injection, burning sensation, severe pain, in rare cases, febrile symptoms can be felt. Since the drug is quickly distributed throughout the circulatory system, if the procedure is carried out in a hurry, in violation of the dilution technique, dizziness, lowering blood pressure, up to a swoon, may occur. In an unequipped room, in the absence of qualified personnel, first aid may not be provided on time.
Liquid solutions
Drugs can be produced in ampoules or in bottles, manufactured at specialized factories. To determine the pharmacology of the dosage form for injection, information regarding the name, volume, concentration, date of manufacture and expiration date is applied.
Using a medical solvent (for example, distilled water, fatty oils, alcohols), a solution can be prepared for subsequent use. Powder dosage forms for injection are diluted with sodium chloride, glucose, novocaine. As a result, the liquid should not contain impurities; the sediment is usually transparent.
Injection solvents
The use of liquid is necessary to dissolve the powder form of the drug. The solution is called “Water for Injection”, its price is relatively low, you can purchase it in any pharmacy network. During use, water is collected from the ampoule and poured into a bottle with the drug, diluted so that there are no small lumps left.
When writing a prescription for injectable dosage forms, the doctor usually indicates which solvent will need to be additionally purchased. Non-aquatic include oil, for example, castor, olive, cotton, coconut or peach. It must be deodorized, refined. Due to the fact that the oil is viscous in its structure, injections with them are painful, there is a risk of granulomas. Ethyl ether may be used to slightly reduce viscosity.
If the doctor has prescribed B vitamins in ampoules for injection, then ethyl oleate can be used as a solvent. It has a better ability to dilute the drug, easier to absorb than oil. Suitable for hormonal dosage forms. When prescribing vitamins A and D, antibiotics, barbiturates, sulfonamides, alkaloids bases, propylene glycol is used.
Ethanol is chosen as an antiseptic and a solvent for injectable preparations of cardiac glycosides (strophanthin K, convallatoxin). In the latter case, glycerin also copes with this role. Using it, injections of fetanol, mesatone, dibazole and others are made.
Application methods
Depending on which part of the body an injection is made, it is customary to distinguish the following methods of application:
- Intramuscular
- Subcutaneous and intradermal.
- Intravascular, intracavitary and intraosseous.
- Under the shell of the brain.
Most of the above is carried out only by qualified medical personnel in a medical institution. Intramuscular, as a rule, many can do at home. Dexterity, sterility and confidence in one’s own actions are important here.
Intramuscular
The appointment of immunomodulatory drugs by a doctor is usually limited to B vitamins. In ampoules for injection, you can buy it at any pharmacy. The clear liquid has a yellowish-greenish tint, with a characteristic smell of thiamine. The medicine is injected intramuscularly into the femoral, deltoid or gluteal muscle, at an angle of 90 degrees. Some vitamin groups can be administered intravenously.
For one application, from 1 to 20 ml of solution is administered, in some cases, if there are indications of 50-70 ml. The form of the drug can be any, suspension for injection, oily, aqueous solutions, emulsions. It should be understood that the absorption process can occur slowly, therefore, it is recommended to stay at rest for some time after the procedures.
Oil solutions, suspensions, emulsions provide a gradual intake of the drug into the body, creating a kind of “depot”. These include hormonal contraceptives, anabolic steroids. This form extends the duration of the drug, in some cases for several months. After the procedure, it is necessary to ensure that a post-injection abscess does not form.
In addition to the above drugs, vaccines against influenza, hepatitis A, rabies, morphine, penicillin, prednisolone, codeine and others can be administered intramuscularly. All of them are prescribed by the attending physician and cannot be recommended for self-treatment.
Intradermal and subcutaneous
All injection dosage forms must be packaged in sterile containers. Intradermal injected into the upper layer of the epidermis, a fluid volume of 0.2-0.5 ml, for example, "Tuberculin." It is known to many when a Mantoux test is done. In this case, the needle is used with a beveled tip; as a result of drug administration, a bubble forms under the skin, a small seal.
During subcutaneous injections, the needle reaches subcutaneous fat. The volume of a one-time administered drug is 1-2 ml. If drip injections are used, then up to 500 ml of solution can be administered once. Subcutaneous, in which emulsions in dosage form are used for injection, quickly enter the bloodstream and spread throughout the body. As a rule, the procedure is carried out in the area of ​​the inner surface of the arm, lower abdomen, thighs.
The most important types of medications: insulins and heparins. If it is necessary to prolong their action, then oil solutions, emulsions or suspensions are used as a diluent. Why you may need to install a special device that contains a microcapsule of the drug in the metering grid.
The absorption rate depends on the composition of the solvent for the preparation of dosage forms for injection. Slowest of all it occurs in oil, and water, on the contrary, penetrate the body faster. The main requirement when carrying out this type of procedure is the possession of a sufficient number of skills. Since there is a high probability of damage to soft tissues, the formation of hematomas. As a rule, when applying a warm and moist compress, the infiltrates quickly resolve.
Intravascular, intracavitary, and intraosseous procedures
Intravascular include intra-arterial (it can be the brachial, carotid or femoral artery) and intravenous (injected into the subclavian or ulnar). As a solvent, phosphate or erythromycin ascorbate is used. The solution should be aseptically prepared, completely sterile. The effect of the administration of the dosage form is achieved in seconds.
If we talk about intravascular injections, then a special system is used for the injection of liquid dosage forms. The consequences of an incorrect procedure:
- hematoma, which is formed as a result of damage to a vein;
- air embolism (blockage of a blood vessel by air bubbles);
- damage to nerve endings;
- through puncture of a vein.
It is imperative that you trust an intramuscular injection to qualified medical personnel.
A distinctive feature of intravascular procedures is the use of only water-based solutions. They should not lead to the formation of blood clots, hemolysis of red blood cells, and also not have a detrimental effect on the walls of blood vessels. It is worth buying sterile water for injection, the price is low, moreover, it is sold in a pharmacy near the house.
If the field of application of the drug is in a specific artery, then intra-arterial administration will locally affect it. Carrying out intracavitary and intraosseous procedures should be carried out in a specialized medical institution, by a qualified specialist.
Under the shell of the brain
This species is used for intracranial and spinal injections. The first method is resorted to with the introduction of a streptomycin solution in case of meningitis. The dosage form of the solution can only be an aqueous, neutral reaction, the volume of a single-injection drug is one to two milliliters. The effect of the application is achieved immediately. The procedure can only be performed by a doctor or an experienced nurse in a medical facility.
The second method is often found with the introduction of anesthetics or antibiotics. The solution can only be water-based, have a neutral pH of 5 to 8. The location for the procedure inside the epidural and subarachnoid space between the 3rd and 4th lumbar vertebra. The danger of an unqualified injection is the risk of damage to the terminal thread of the spinal cord, as a result of which paralysis of the legs can occur. Carried out in a medical institution.
Basic rules of application
It is important to comply with the requirements for dosage forms for injection, to control the date and end date of use, the temperature regime during storage. For the procedure, it is necessary to prepare the inventory: a syringe with a needle, alcohol wipes, a solution for dilution, an ampoule with the drug. It is important to observe the storage conditions of dosage forms and injections in order to prevent the use of a spoiled preparation.
Safety measures include carrying out the procedure with clean hands, preferably treated with alcohol. Before preparing for the injection, you need to choose the right syringe. It can be of different volumes, two- and three-component, imported or Russian-made.
The needle is attached to the syringe, the liquid is shaken off the tip of the ampoule, for example, by lightly tapping with a finger. If the ampoule is glass, then along the incision line it must be filed with a special device (usually comes with the drug). To protect your fingers, you can wrap it with a gauze napkin and break it into place. Next, you need to collect the solution from the ampoule and squeeze out the excess air with a piston from the syringe.
If the injection is done intravenously, then you will need to pull the arm above the elbow with a tourniquet, and immediately after the procedure, it is weakened. The injection site is treated with an antiseptic. Before you enter the medicine, check if the needle is in the vein or not. To do this, the piston is pulled back until it shows blood inside the syringe. If its color is dark, then you can enter the drug. It happens that the location of the veins in the elbow does not allow the procedure and then it may be necessary to introduce the drug on the back of the wrist. To avoid the formation of a hematoma, the arm bent at the elbow must be held for 5 minutes.
Intramuscular injections do not require special preparation by the patient. Those who carry out the procedures should know in which area the injection is necessary. By visually delimiting the buttock region into four parts, it is possible to determine the optimal zone for manipulations. The best place is the upper outer square. Thus, it is possible to avoid getting the drug into the sciatic nerve. If you inject yourself, you can choose the area of ​​the front surface of the thigh, however, this is not very convenient.
During intramuscular injection, the main condition is the gradual introduction and smooth descent of the piston. The optimal length of the needle is not more than 5 cm. This will reduce pain during the procedure and dispense with post-injection seals. If the drug is administered too quickly, the patient may feel severe pain, the formation of stagnation of the drug is possible and further bumps at the injection site can not be avoided.
After completing the manipulations, the working surface must be cleaned. Discarded vials, syringe, cotton swabs.