A therapeutic drug can enter the body in various ways. Routes of administration of drugs are determined by the speed of the therapeutic effect, its severity and duration. In some cases, the nature of its action, and, therefore, our recovery, depends on how the medicine entered the body. There are several basic methods of administering drugs inside, and each of them has its pros and cons. Before you figure out which route of administration to choose, you need to know exactly what forms of medication exist.
The main forms of drugs
Before you determine the route of administration of drugs into the body, you need to know what types of drugs exist, and there are many:
- Solutions are a liquid form of the drug. They are a medicinal substance diluted in water, alcohol, glycerin or another solvent. But it is worth remembering that a high-quality and unspoiled solution should be transparent, no cloudy sediment or foreign particles. They can be used for both parenteral and enteral administration.
- Decoctions and infusions - these funds are prepared from plant materials. But it is worth remembering that they are not stored for a long time, no more than 3 days in a cool place and protected from sunlight.
- Pills are a solid form of medicine that is obtained by compression. Basically, they are taken orally, but an external route of administration of drugs is also possible if they are crushed into powder.
- Dragee - this is another kind of solid form of medicines , they are created by layering the main substance on a granule. Use for oral administration.
- Capsules - a solid form of medicine, is a tablet coated with a shell of gelatin or another substance. Most often, capsules contain drugs with a bitter aftertaste or a specific smell, thanks to the shell, the reception of these funds is greatly facilitated. In addition, it allows you to protect the substance from rapid destruction in the digestive tract.
- Candles are a dosage form of the drug that remains at solid temperature at room temperature, but melts inside the human body. If we consider the introduction of drugs, there are two types of pathways for suppositories - rectal and vaginal.
- A patch is a plastic form of a product that softens under the influence of body temperature and easily adheres to the skin. Suitable for external use only.
- Ointments are a viscous consistency agent, used mainly for external use. They must contain in their composition about 25% solids.
There are several ways to administer drugs, we will consider each of them in more detail.
Types of Enteral Administration
The enteral route of administration of drugs is considered one of the most convenient and safe. There are several subspecies of this path: oral, sublingual, rectal.
1. Oral administration of the drug, in other words, oral administration is one of the simplest methods, which is why it is most often prescribed by many doctors. The absorption of drugs received in this way occurs mainly by diffusion in the small intestine, in rare cases, in the stomach. The effect of the application is noticeable after 30-40 minutes. For this reason, this method is not suitable for emergency assistance. The speed and completeness of absorption depend on the meal, its composition and quantity. Thus, if you drink the medicine on an empty stomach, then absorption of weak bases improves, because the acidity in the stomach is low, but acids are better absorbed after eating. But there are also drugs, such as Calcium Chloride, which, when ingested after ingestion, can form insoluble calcium salts, which limits their ability to be absorbed into the blood.
2. Another convenient and effective enteral route of drug administration is sublingual. The medicine is placed under the tongue, thanks to a large network of capillaries in the mucous membrane, it is absorbed very quickly. The effect comes in a few minutes. This method of administration is most often used for the use of Nitroglycerin for angina pectoris, Klofelin and Nifedipine to eliminate the hypertensive crisis.
3. The rectal route is not used very often. It is mainly used if the patient has gastrointestinal diseases, or if he is in an unconscious state.
Enteral administration: advantages and disadvantages
All ways and methods of drug administration have their advantages, they also have an enteral:
- Simplicity and ease of use.
- Naturalness.
- Relative safety for the patient.
- It does not require sterility, observation by the medical staff.
- The possibility of long-term therapy.
- Comfort for the patient.
But there are also disadvantages of the enteric route of administration of drugs:
- The effect is slow.
- Low bioavailability.
- Different speed and completeness of absorption.
- The effect of food intake and other components on the absorption process.
- Inability to use by patients in an unconscious state.
- It is undesirable to use in patients who have pathologies of the stomach and intestines.
Types of parenteral administration
The parenteral route of administration of drugs involves the introduction of drugs without involving the digestive system. It can be divided into several types.
In fabric:
- Intradermally - this method is mainly used for diagnostic purposes, for example, for allergic tests of Burnet or for local anesthesia.
- Subcutaneously - used if you want to get the maximum effect from the drug. This is achieved due to the fact that the subcutaneous fat layer is well equipped with blood vessels, and this contributes to rapid absorption.
- Intramuscularly - used if subcutaneous administration causes irritation or pain, and also when the drug itself is slowly absorbed.
- Intracranial - this method is used infrequently, mainly with extensive burns and deformation of the extremities, when other options cannot be applied.
If there is an introduction of drugs, the paths through the vessels are as follows:
- Intravenously - this method is used to administer a large number of drugs and some drugs that have such a requirement for use.
- Intraarterial - used in terminal conditions that are caused by shock, large blood loss, asphyxia, electric shock, intoxication and infections.
- In the lymphatic vessels - this method is used so that the medicine does not enter the liver and kidneys, to ensure a more accurate contact with the focus of the disease.
Intravascular administration of drugs is not always convenient, paths can also lead through cavities:
- Pleural.
- Abdominal.
- Hearts.
- Joint.
Parenteral Administration: Pros and Cons
Parenteral administration has several advantages:
- This method allows you to enter the drug bypassing the digestive tract, which is very important for patients with serious stomach pathologies.
- Speed of action is necessary in emergency situations.
- Maximum dosage accuracy.
- The drug is released into the blood unchanged.
The parenteral route of administration of drugs has several disadvantages:
- Be sure the drug must be administered by a trained medical professional.
- Compliance with asepsis and antiseptics is required.
- Difficult and even impossible administration of the drug with bleeding, damage to the skin at the injection site.
Inhalation
The inhalation route of drug administration allows the use of aerosols, gases (volatile antiseptics) and powders (sodium chromoglycate) in the treatment . With this method of administration, the drugs quickly enter and exert their therapeutic effect. In addition, it is easy to control the concentration of the drug in the blood - the cessation of inhalation leads to the suspension of the drug. By inhalation of an aerosol, the concentration of the agent in the bronchi is very high with a minimal systemic effect.
But it is worth remembering that no matter how effective the inhalation, it does not allow the use of irritating substances. You also need to keep in mind that inhaled drugs can affect others (for example, anesthesia).
Pros and Cons of Inhalation
We continue to consider the route of administration of drugs. Advantages and disadvantages has the inhalation method. Pros of inhalation:
- It acts directly in the pathology site.
- The medicine easily penetrates the site of inflammation, while bypassing the liver unchanged, which causes its high concentration in the blood.
Cons of inhalation:
- If bronchial patency is severely impaired, then the drug does not penetrate the focus of the disease.
- Drugs can irritate the mucous membranes of the nose, mouth, and throat.
The main routes of drug administration have been considered, but there are others that can also become indispensable in some cases.
Rectal, vaginal and urethral routes of administration
If we compare the rectal route of administration of drugs with oral administration, then we can say for sure that the effect of the first method occurs much faster. The drug is rapidly absorbed into the blood without being destroyed by enzymes of the digestive tract and liver.
Rectal injected into the body candles, ointments, as well as other forms of drugs previously ground into powder and diluted, while using enemas. But it is worth remembering that a solution administered rectally will give an effect much faster than a candle. The enema volume for adults is from 50 to 100 ml, and for children from 10 to 30 ml. But this method of drug administration has disadvantages:
- Inconvenient use.
- Special fluctuations in speed and full picture of absorption.
That is why the rectal route of administration is recommended to be used only in cases where oral administration is difficult, when it is necessary for the drug to enter the blood quickly and injections are contraindicated for one reason or another.
Vaginal and urethral methods allow you to enter any form of drugs. But both of these methods give the best result if they are used to treat infections in these organs or to conduct diagnostics, for example, for the administration of contrast agents, such as Iodamide, Triombrast and others.
Spinal and intracranial routes of administration
In very rare cases, spinal and intracranial (suboccipital, subarachnoid, subdural and others) injections are used. This is mainly due to the fact that only a qualified specialist should administer the drug with such methods. Such methods require the use of only sterile, completely transparent, true aqueous solutions with a neutral reaction. The action comes very quickly.
Transdermal therapeutic systems
Recently, drugs in a new form are increasingly appearing. Transdermal therapeutic systems (TTCs) are one of them. They are a soft dosage form intended for external use with a slow release of the drug substance. Modern TTS are films and plasters that have been manufactured using cutting edge technology and are very convenient to use: the patch is glued to the skin, and the film is laid on the cheek. In this case, the main substance is absorbed into the blood through the skin or mucous membrane.
Many doctors around the world have recently been paying more attention to the latest ways of administering drugs. Everyone has advantages and disadvantages, including the TTC. Consider the pros:
- The medicine is acting at an accelerated pace.
- The drug enters the bloodstream gradually without interruption, which ensures a stable level of the main substance.
- Unpleasant sensations are completely excluded, this applies to gagging, and pain from injections.
- The complete absence of undesirable effects from the digestive tract.
- Reducing the frequency of allergies.
- The possibility of rapid drug withdrawal, if there are suddenly contraindications.
- The exact dosage.
- The possibility of targeted delivery of the drug to the desired part of the body.
Each of the described routes of administration of drugs has its pros and cons. But no matter how good the method may be, the main thing is that the doctor should prescribe it, and it is desirable that the most complex and rare methods of administration are carried out by a specially trained person in a medical institution. Take care so you don’t have to think about how to deliver the medicine inside the body.