Antimicrobial spectrum and mechanism of action
The drug demonstrates high efficacy against gram-negative flora, destroying microorganisms both in the division phase and in the resting phase. Ciprofloxacin acts moderately against gram-positive flora, and only during the period of cell division. The drug is practically ineffective against anaerobes.
Target pathogens for the drug include:
- Enteric group and enterobacteria (Escherichia coli, Salmonella, Shigella, Klebsiella, Proteus, Helicobacter);
- Specific pathogens (meningococci, gonococci, Haemophilus influenzae);
- Nosocomial flora, including Pseudomonas aeruginosa and staphylococci;
- Intracellular pathogens (Chlamydia, Legionella, Brucella, and Mycobacterium tuberculosis).
Pneumococci, streptococci, enterococci, and mycoplasmas exhibit low sensitivity to the drug.
Pharmacokinetics and dosage forms
Upon oral administration, the bioavailability of ciprofloxacin reaches 60–80%. Food intake can slow down the absorption of the active substance, but the overall bioavailability does not decrease. The drug distributes exceptionally well into organs and tissues, crossing the blood-brain barrier (BBB).
The treatment regimen involves taking the drug at 12-hour intervals. The pharmaceutical industry produces the agent in various dosage forms:
- For oral administration;
- Parenterally (intravenously);
- Topically (eye and ear drops, as well as eye ointment).
Clinical application
The broad spectrum allows ciprofloxacin to be prescribed for inflammatory processes of various localization:
- ENT organs: sinusitis, maxillary sinusitis, otitis media, tonsillitis, and pharyngitis;
- Lower respiratory tract: bronchitis and pneumonia;
- Urinary system and pelvis: cystitis, pyelonephritis, prostatitis, and endometritis;
- Musculoskeletal system: arthritis and osteomyelitis;
- Skin: infected burns, ulcers, wounds, and abscesses;
- Abdominal cavity: intestinal bacterial infections, as well as surgical perioperative prophylaxis;
- Ophthalmology: conjunctivitis, keratitis, and blepharitis;
- Phthisiology: complex tuberculosis therapy.
In addition, the drug has special indications: anthrax prophylaxis and tularemia treatment.
Safety and drug interactions
When using ciprofloxacin, it is important to consider potential gastrointestinal side effects. A specific complication of therapy is pseudomembranous colitis associated with Clostridium difficile activity.
Among drug interactions, the effect on the metabolism of theophylline is of key importance. The antibiotic inhibits its breakdown, leading to an increase in blood theophylline concentrations and amplification of its toxic effects.
Briefly: answers to topical questions
Which liver enzymes does ciprofloxacin inhibit when interacting with theophylline?
When interacting with theophylline, ciprofloxacin inhibits the hepatic microsomal isoenzyme CYP1A2. This leads to slowed theophylline metabolism and increased concentration in the systemic circulation. As a result, a sharp increase in drug toxicity occurs along with an elevated risk of toxic effects (effectus toxici).
What are the main musculoskeletal side effects characteristic of fluoroquinolones?
Fluoroquinolones are characterized by chondrotoxicity and specific tendon damage. The main musculoskeletal side effects include:
- Arthropathies — joint damage.
- Arthralgias — joint pain.
- Myalgias — muscle pain.
- Tendinitis — inflammation of the tendons with a risk of rupture (especially when combined with physical exertion and glucocorticoid intake).
- Impaired cartilage development — damage to bone and cartilage tissue (causing arthralgia in children).
What is the mechanism of the bactericidal action of fluoroquinolones?
The mechanism of the bactericidal action of fluoroquinolones is related to their effect on topoisomerase enzymes. The drugs exert a bactericidal effect on Gram-negative flora in both the division and resting phases, and on Gram-positive flora only in the division phase. The selectivity of action is due to the fact that suppressing human topoisomerase II requires ultra-high concentrations. The development of bacterial resistance occurs through chromosomal mutations in genes encoding topoisomerases, leading to an alteration of the antibiotic's target.
What are the contraindications for prescribing ciprofloxacin?
Contraindications for prescribing ciprofloxacin are primarily associated with the risk of cartilage damage. The main contraindications include:
- Pediatric age — under 18 years (use in children is possible exclusively for life-saving indications).
- Pregnancy — due to damaging effects on the bone and cartilage tissue of the fetus.
- Lactation period — breastfeeding.
Additionally, a general contraindication is a confirmed allergy or hypersensitivity reactions to drugs of this group.
Which agents belong to the first, second, third, and fourth generations of fluoroquinolones?
The provided educational materials describe only first- and second-generation fluoroquinolones, the classification of which is based on their spectrum of action and chemical structure.
| Generation | Representatives |
|---|---|
| 1st generation | Ciprofloxacin, lomefloxacin, norfloxacin, ofloxacin, pefloxacin, enoxacin |
| 2nd generation | Levofloxacin, sparfloxacin, moxifloxacin |
Information on third- and fourth-generation drugs is not presented in these sources.
Ciprofloxacin provides a "broad strike" against Gram-negative bacilli and
Class and exam questions
Which generation does Ciprofloxacin belong to?
The drug is a representative of second-generation fluoroquinolones.
How does food affect drug absorption?
Food intake slows down the absorption of ciprofloxacin, but does not decrease its overall bioavailability, which is 60–80%.
What specific gastrointestinal complication may develop during administration?
A frequent specific effect is pseudomembranous colitis associated with the proliferation of Clostridium difficile.
What else to study on this topic
- Peculiarities of action on Gram-negative and Gram-positive flora in different phases of the cell cycle
- Spectrum of target pathogens, including hospital strains and Pseudomonas aeruginosa
- Pharmacokinetic parameters: blood-brain barrier penetration and bioavailability
- Complete list of organ-system indications ranging from ENT pathologies to phthisiology
- Pharmacological interaction with theophylline and the mechanism of its increased toxicity
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