Mechanism of action and biochemistry of the process
In pharmacology, hydrogen peroxide is classified as an antiseptic from the group of oxidizing agents. To understand the logic behind this group's action, one must examine the basic mechanism of antimicrobial activity. All oxidizing agents work on the same principle: when they break down in tissues, oxygen is released. This gas enters into aggressive chemical reactions, oxidizing vital biomolecules inside the microbial cell. Damage to structural elements inevitably causes the microorganism to die.
However, within the group, there is a strict hierarchy of activity that depends on the form of released oxygen. Drugs can generate either atomic or molecular oxygen. Comparative activity shows a clear picture: agents that release atomic oxygen have a much stronger and more pronounced antiseptic effect. Hydrogen peroxide is the main and most famous representative of the part of the group that releases precisely molecular oxygen.
The key factor that triggers the drug's action in the body is the tissue enzyme catalase. As soon as the solution gets onto damaged tissues, mucous membranes, or into a wound, catalase comes into contact with the drug molecules and catalyzes the reaction of its decomposition. The biochemical equation of this process is as follows: $H_2O_2 \rightarrow 2H^+ + O_2$. Hydrogen ions and the very same molecular oxygen, which is responsible for all subsequent clinical effects, are produced as a result.
Pharmacodynamics: three main effects
The pharmacodynamics of the drug are quite specific. Unlike many other antiseptics, its main value lies not in the direct destruction of bacteria, but in the physicochemical properties of the released gas.
- Mechanical cleansing (main effect). This is the basic function of the drug in surgical practice. At the moment of contact with catalase and the breakdown of molecules, an extremely vigorous release of gas bubbles occurs. The liquid instantly turns into a voluminous, dense foam. This foam has a powerful pushing action: it mechanically washes accumulations of pus, necrotic (dead) tissues, dirt particles, and other foreign bodies out of deep wound pockets. Effective sanitation of the wound bed takes place.
- Hemostatic effect. The second most significant effect is the local cessation of bleeding. The drug interferes with the coagulation cascade at a local level. Under its influence, the clotting of fibrinogen—a soluble blood plasma protein—is accelerated. As a result, a thrombus is formed, which reliably plugs the lumen of the damaged vessel.
- Bactericidal effect. It is important to emphasize that the drug's ability to kill microorganisms is assessed as insignificant. This is a direct consequence of its biochemical mechanism. Since the reaction with catalase releases molecular oxygen (rather than aggressive atomic oxygen), the strength of its oxidizing effect is insufficient for the total destruction of the microbial cell's biomolecules.
Clinical indications
In medical practice, the standard is the use of a 3% hydrogen peroxide solution. The use of the drug spans several medical disciplines where its cleansing and hemostatic properties are required.
- Surgery and traumatology. Here, the drug is a routine agent for primary wound care. It is especially indicated in the presence of heavily contaminated and purulent wounds, where thorough mechanical cleansing is required before further manipulations. The solution is also actively used to stop bleeding from superficial wounds.
- Cessation of specific bleeding. Due to its ability to accelerate the clotting of fibrinogen, the drug is a classic agent for stopping capillary bleeding. Its role in stopping epistaxis (nosebleeds) deserves separate mention: gauze tampons heavily moistened with a 3% solution are inserted into the nasal cavity for rapid local hemostasis.
- Dentistry and ENT practice. The drug's ability to wash out pathological contents and cleanse surfaces has found application in the treatment of inflammatory diseases of the mucous membranes. The solution is prescribed as a mouthwash for stomatitis (inflammatory processes in the oral cavity) and tonsillitis. The foam helps remove purulent coatings and inflammation products.
Briefly: answers to topical questions
Which antiseptics from the oxidizing agents group release atomic oxygen?
The oxidizing agents group includes drugs that release atomic oxygen, which has a stronger antiseptic effect than molecular oxygen.
- Potassium permanganate (Kalii permanganas) — upon contact with water, atomic oxygen is split off, which is a powerful oxidizing agent.
What are the contraindications for the topical use of hydrogen peroxide?
For hydrogen peroxide, sources indicate the following cases when its use is contraindicated or unacceptable:
- Introduction into the vascular bed — hydrogen peroxide is listed among substances contraindicated for introduction into the vascular bed.
- Endodontics — during the biological method of pulpitis treatment, the use of strong antiseptics, including 3% hydrogen peroxide, is categorically unacceptable.
- Medical treatment of a carious cavity before filling — hydrogen peroxide is contraindicated because it leads to the saturation of tooth tissues with oxygen and the formation of an unfavorable inhibited layer of the composite.
What concentrations of hydrogen peroxide solutions are used in medical practice?
In medical practice, hydrogen peroxide solutions are used in various concentrations depending on the medical tasks and treatment methodology.
- 3% aqueous solution — used in dentistry, ENT practice, surgery, and traumatology for rinsing, primary treatment of contaminated and purulent wounds, fistulae, abscesses, and stopping bleeding.
- 2.5% solution — used in combination with a detergent during pre-sterilization preparation of instruments.
- 6% solution — used in combination with a detergent for processing instruments after operations involving anaerobic infection.
To remember the effects of peroxide, recall the abbreviation POK: Pena (foam / mechanical cleansing), Ostanovka krovi (stopping blood / fibrinogen hemostasis), Katalaza (catalase / target enzyme).
Class and exam questions
Why does hydrogen peroxide weakly kill bacteria?
Because upon its breakdown in tissues, molecular oxygen is released. It has a much lower oxidizing activity compared to atomic oxygen, so its bactericidal effect is insignificant.
How does the drug stop bleeding?
The hemostatic effect is due to the fact that the drug locally accelerates the clotting process of the protein fibrinogen. This leads to the rapid formation of a blood clot in small capillaries and superficial wounds.
Why is foam needed when treating a wound?
The vigorous release of gas bubbles and the formation of foam provide the drug's main effect — mechanical cleansing. The foam physically washes pus, dead tissues, and foreign bodies out of the wound.
Which enzyme makes peroxide foam?
The decomposition reaction of the drug with gas release is triggered by the tissue enzyme catalase, which is normally present in the body's cells.
What else to study on this topic
- Drugs releasing atomic oxygen: activity comparison
- Biochemistry of the enzyme catalase and the rate of the decomposition reaction
- The mechanism of fibrinogen clotting in capillary bleeding
- Features of using oxidizing agents in purulent wounds
- Protocols for using a 3% solution in stomatitis and tonsillitis
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