Classification of adverse reactions
All adverse events associated with antibacterial drugs are systematically classified into four key groups:
- Allergic — reactions developing due to a direct effect on the protective immune system.
- Toxic — pathological conditions caused by the direct chemotherapeutic effect of the drugs.
- Organotropic — specific damage to particular anatomical organs.
- Mixed — complex disorders combining several development mechanisms.
Superinfections and dysbiosis
Suppression of normal microflora by broad-spectrum antibiotics often leads to the development of secondary infectious complications:
- Candidiasis: develops due to the suppression of normal flora. Fungal infection can affect the oral cavity, intestines, and urogenital tract. Antifungal agents, such as nystatin, are used for correction.
- Pseudomembranous colitis: a severe condition caused by the active proliferation of the microorganism Clostridium difficile amidst the destruction of competing bacteria. The main clinical marker is bloody diarrhea. Drug groups that provoke colitis include penicillins, cephalosporins, fluoroquinolones, and lincosamides.
Organotoxic effects
Certain medicinal agents have a direct damaging effect on the tissues of internal organs and systems:
- Hepatotoxic effect: characteristic of macrolides, glycopeptides, rifampicin, and tetracyclines.
- Nephrotoxic effect: observed with the use of aminoglycosides, certain cephalosporins (e.g., cefamandole), polymyxins, and glycopeptides.
- Hematotoxic effect: noted with the use of chloramphenicol, which carries the risk of developing aplastic and hemolytic anemia, as well as agranulocytosis.
Briefly: answers to topical questions
What are the main mechanisms of allergic reactions to antibiotics?
The primary mechanism of allergic reactions to antibiotics is an immune response to the drug acting as an allergen or hapten. The drug binds to plasma proteins, forming a complex with antigenic properties, which leads to antibody production and body sensitization. The reaction occurs upon repeated administration of the drug and is dose-independent.
The following mechanisms (types of hypersensitivity) are distinguished:
- Type I (IgE-mediated) — an immediate reaction causing anaphylactic reactions to antibiotics (urticaria, skin rash, pruritus, angioedema, anaphylactic shock).
- Type IV (DTH) — a cell-mediated immune response causing contact dermatitis to antibiotics and drug-induced interstitial nephritis.
What other antibiotics cause hematotoxicity besides chloramphenicol?
In addition to chloramphenicol, antibacterial drugs from the lincosamide group cause a hematotoxic effect. The safety profile of this antibiotic group highlights the following blood system side effects:
- Transient neutropenia.
- Thrombocytopenia.
No other antibiotics with a hematotoxic effect are indicated in the provided sources.
Classification of the 4 groups: ATOS (Allergic, Toxic, Organotropic, Mixed).
Class and exam questions
How many groups are antibiotic side effects divided into?
All adverse reactions are systematically classified into 4 main groups: allergic, toxic, organotropic, and mixed.
Which microorganism causes pseudomembranous colitis?
The disease is provoked by the active proliferation of the bacterium Clostridium difficile, which occurs amidst the destruction of normal competing flora caused by antibiotics.
Which antibiotic groups exhibit nephrotoxic effects?
Aminoglycosides, select cephalosporins (including cefamandole), polymyxins, and glycopeptides possess nephrotoxic properties.
What else to study on this topic
- Detailed analysis of the mechanisms of allergic reactions
- Spectrum of pathogens in gastrointestinal candidiasis
- Features of pharmacotherapy in liver and kidney damage
- Clinical presentation of aplastic anemia associated with chloramphenicol intake
- Prevention of dysbiosis during antibiotic therapy
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