Pharmacological effects and spectrum of activity
Ethanol exerts diverse effects on tissues and microorganisms. Its key properties include:
- Antiseptic and disinfectant;
- Local irritant;
- Tanning (on skin and mucous membranes).
The microbiological spectrum covers Gram-positive and Gram-negative bacteria, as well as viruses.
Dependence of application on concentration
The choice of Spiritus aethylicus solution is determined by the medical task:
- 90–95% — used for disinfection of surgical instruments due to its pronounced tanning property.
- 70% — the optimal concentration in terms of permeability, used for preparing the surgeon's hands and the operative field.
- Various concentrations — used topically as an irritant for applying compresses and rubs.
Ethanol-based combination drugs
To expand the antimicrobial spectrum, complex agents are created. A prominent example is Hospisept, a combination drug containing ethanol and propanol.
Its activity extends to:
- Bacteria (Gram+ and Gram-), as well as fungi;
- Viruses, including causative agents of parenteral hepatitis B and HIV.
The drug is in demand for the hygienic treatment of medical personnel's and surgeons' hands, as well as for treating the skin of the injection site.
Briefly: answers to topical questions
What are the pharmacokinetic features of ethanol absorption and metabolism in the body?
Ethanol (Spiritus aethylicus) is rapidly absorbed from the stomach and small intestine, easily penetrating cells. Metabolism has gender differences: in men, it is accelerated due to higher activity of hepatic microsomal enzymes.
Features of elimination and metabolism:
- Excretion in unchanged form — 5–10% is excreted via urine, feces, sweat, milk, and exhaled air.
- Oxidation — 90% is metabolized in the liver at a rate of 5–10 ml/h.
The biochemical pathway involves the conversion of ethanol by alcohol dehydrogenase into highly toxic acetaldehyde. Further, aldehyde dehydrogenase and Krebs cycle enzymes oxidize it to water and carbon dioxide. The process is accompanied by an excess of NADH, which inhibits gluconeogenesis and stimulates lactate production. Alcohol dehydrogenase is completely absent in the fetus.
What symptoms develop in acute ethanol poisoning and what are the principles of management?
Acute ethanol poisoning causes a depressant effect on the central nervous system up to alcoholic coma, which can be fatal. The clinical picture depends on the blood alcohol concentration: at 1.5 g/L, noticeable manifestations of intoxication appear, at 3.5 g/L — pronounced, and 4–8 g/L is the median lethal dose.
Symptomatology may be accompanied by loss of consciousness and metabolic disorders:
- Hypoglycemia — decrease in glucose levels due to inhibition of gluconeogenesis.
- Lactic acidosis — hyperlactatemia resulting from the shift in the equilibrium of the lactate dehydrogenase reaction towards lactate formation.
The cited sources do not disclose specific management principles specifically for acute ethanol poisoning.
What drug interactions are characteristic of ethyl alcohol?
Ethyl alcohol enters into clinically significant drug interactions, predominantly enhancing the toxicity or depressant effect of other drugs.
Main drug interactions of ethanol:
- Potentiation of CNS depression — mutual enhancement of effects when taken with sedatives, benzodiazepine receptor agonists, tiagabine, and clonidine.
- Disulfiram-like reaction — metronidazole inhibits aldehyde dehydrogenase and, when alcohol is taken, delays ethanol oxidation at the acetaldehyde stage, causing intoxication. Cefotetan and cefoperazone cause a disulfiram-like reaction by blocking ethanol metabolism enzymes, which manifests as alcohol intolerance upon co-administration.
- Enzyme induction — chronic alcohol consumption induces the CYP2E1 isoenzyme, sharply increasing the formation of the hepatotoxic metabolite of paracetamol.
In addition, the antifungal drug griseofulvin is able to enhance the toxic effects of alcohol.
70% — for hands and skin (optimal permeability), 90–95% — for severe tanning of instruments.
Class and exam questions
Why is a 70% solution used for the surgeon's hand prep rather than a 95% solution?
A 70% concentration provides optimal antiseptic tissue permeability. Higher concentrations (90–95%) cause a sharp tanning effect, which prevents deep penetration.
Which microorganisms are sensitive to ethanol?
The substance is active against viruses, as well as Gram-positive and Gram-negative bacteria.
What is the composition of the combination drug Hospisept?
The drug is a combination of ethanol and propanol, which provides an expanded spectrum of activity against bacteria, fungi, and viruses (including HIV and hepatitis B).
What else to study on this topic
- Effect of ethanol on protozoa and fungi
- Mechanism of the tanning effect on skin and mucosal proteins
- Comparative characteristics of Hospisept and single-component drugs
- Features of surgical hand antisepsis
- Application of external alcohol compresses
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