General properties and mechanism of antimicrobial action
The pharmacological properties of aldehydes and alcohols are based on their ability to exert powerful microbicidal action. The entire process of microbial destruction can be divided into two consecutive stages:
- Profound dehydration of microbial cells.
- Irreversible coagulation of protoplasmic proteins.
As a result of these physicochemical processes, the cell loses viability and dies. The spectrum of antimicrobial activity covers a wide variety of pathogens: bacteria (including vegetative forms and spores), fungi, and viruses.
Formaldehyde solution and anti-perspiration agents
The formaldehyde solution itself is distinguished not only by a pronounced antimicrobial spectrum, but also by a powerful tanning effect on tissues. This specific property determines its use in combating hyperhidrosis: the tanning action damages sweat glands, thereby reliably suppressing sweat secretion.
In medical practice, formaldehyde is used as a disinfectant and deodorizing agent for processing instruments and care items, as well as in gynecology for diluted douches. For the treatment of excessive sweating, specialized topical preparations have been developed — Formagel and Formidron.
Hexamethylenetetramine (Methenamine, Urotropin)
This substance is a classic prodrug. Its characteristic feature is that it exhibits antiseptic properties strictly in an acidic environment — for example, during inflammation, when the urine reaction shifts to the acidic side.
A bioactivation process occurs: in the urine, the compound breaks down with the release of active formaldehyde, which destroys the pathogenic flora. The effect can be either bactericidal or bacteriostatic depending on the concentration. The main indications are associated with kidney and urinary tract infections, such as cystitis, pyelitis, and urethritis. Today, urotropine is rarely used due to the emergence of more effective analogues.
Policresulen (Vagothyl) and its effects
Policresulen is a copolymer of hydroxymethylbenzenesulfonic acid with formaldehyde. It possesses a wide range of pharmacological effects, including antimicrobial (bactericidal, fungicidal, antiprotozoal), astringent, caustic, keratolytic, and hemostatic action.
The drug is used exclusively topically in several medical disciplines:
- Gynecology: cervical and vaginal erosions, vulvovaginitis, urethral papillomas.
- Surgery and dermatology: poorly healing wounds, leg ulcers, third-degree burns, condylomata acuminata.
- Dentistry: inflammation of the oral mucosa, aphthae, and cessation of bleeding after minor surgical procedures.
Formaldehyde tans the skin and glands (sweat goes away), urotropine works only in acidic urine pools, and policresulen cauterizes and stops bleeding.
Class and exam questions
What is the general mechanism of the antimicrobial action of aldehydes and alcohols?
It includes dehydration of microbial cells and subsequent coagulation of their protoplasmic proteins, leading to microbial death.
Why does formaldehyde solution help reduce sweating?
It exerts a pronounced tanning effect that damages sweat glands and suppresses their secretory activity.
Under what conditions is methenamine (urotropine) activated?
It works only in an acidic environment — for example, in urine during inflammatory processes, where it releases active formaldehyde.
What main effects does policresulen exhibit?
It exhibits antimicrobial, astringent, caustic, keratolytic, and hemostatic (blood-stopping) action.
What else to study on this topic
- Analysis of prodrug bioactivation mechanisms using urotropine as an example
- Comparative characteristics of the local effects of formaldehyde and policresulen
- Features of antiseptic use in urinary tract infections
- Dermatological and surgical indications for agents with keratolytic effects
- Use of tanning agents in the treatment of hyperhidrosis
Master the entire topic in the «Pharmacology» course
This is a summary. The course covers everything tested in classes and exams.
- Complete study guide on "Aldehydes and alcohols" and 5,304 other subject pages
- Assignments and quizzes after every topic — just like in a colloquium
- AI tutor answers questions on the topic anytime
- 116 video lessons on the subject
Other topics in the section «Antiseptics and Disinfectants»
Free video lessons: pharmacologyShort lessons with study notes — no registration required.
Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.