Parenteral drug administration - how is it?
Pharmacodynamics is one of the parts of pharmacology (the science of drugs) that studies the effect of the body on drugs, that is, how drugs are ingested, adsorbed into the bloodstream, transported to organs and tissues, metabolized and removed from it. One of the important issues addressed by pharmacodynamics is the route of administration of drugs. All routes of administration are divided into the integral (through the gastrointestinal tract) and parenteral (bypassing the gastrointestinal tract). And if the first is more or less clear, then parenteral administration of drugs causes a lot of questions in patients.
Injection routes of administration
Among the injection routes, the most common are intravenous and intramuscular. In addition to them, there are also subcutaneous, intracutaneous, intraarterial and intraosseous. Let's break it down, parenterally - how's that?
Intravenous administration of drugs is perhaps the most common among injections. Combining relative simplicity, it provides fast delivery of the drug to organs and tissues with 100% bioavailability. Parenteral administration is a unique opportunity to deliver minimal amounts of drugs, as well as to produce round-the-clock infusion using an established venous catheter and a special device. In addition, the intravenous route is the only way to administer drugs in critical conditions and in cases when the patient is unconscious, and also makes it possible to administer drugs that are poorly soluble in the gastrointestinal tract.
In addition to all the advantages, there are drawbacks to the intravenous route of administration. So, only parenteral agent can be injected intravenously, which is an aqueous solution or suspension on a water basis, and during the manipulation it is necessary to avoid the ingress of air into a blood vessel, as this can lead to the development of an embolism.
Intramuscular administration, at first glance, may seem equivalent to intravenous, but this is far from the case.In addition to lower bioavailability, intramuscular administration is not carried out in critical conditions, since this decreases the central hemodynamics, the blood supply to the muscle tissue decreases and, accordingly, the delivery of drugs decreases. Also do not inject intramuscularly more than 10 ml of solutions.
Intra-arterial administration has found its use in cardiac surgery and angiology, as well as diagnostic procedures. In this case, administering parenterally is like a new breakthrough in medicine, because in this way, for example, the introduction of contrast preparations is carried out to study the vascular system and determine the scope of further therapeutic measures. This, in turn, allows for a new look at the diagnostic process.
Parenteral is how?
Among non-injection routes it is necessary to note the transdermal, intravaginal, intratracheal, as well as intranasal, etc.
The transdermal route is the penetration of drugs through the skin. This way for an adult can cause only a local effect from the drug being administered (for example, in the form of creams or ointments), but in a child the medicinal substances may have a systemic effect.This is due to the fact that the skin of a child has a high sorption capacity, which causes the penetration of drugs into the bloodstream.
Intratracheal administration refers to inhaled routes. In this case, the introduction of the drug occurs through the trachea into the bronchial tree. Typically, this method is the introduction of drugs that affect the respiratory system.
Intranasal administration in the form of sprays and drops, as well as the use of drugs in the form of drops for the eyes, have become widespread.
Which way to choose?
The question of choice is always relevant. If possible, use the oral route should be limited to them, and choosing parenteral administration of drugs, you need to focus on the severity of the patient's condition and the drug itself.
Parenteral drugs are drugs intended for introduction into the human body, bypassing the gastrointestinal tract. The choice of such a route of administration should be based on the principles of rationality, as well as extreme necessity for the patient, since in any case this type of administration is fraught with certain risks.