Products
The first active ingredient in the quinolone group to be introduced was nalidixic acid in 1967 (NegGram). It is no longer commercially available in many countries. Other drugs are available today (see below). Various dosage forms are available, for example, film-coated tablets, oral suspensions, eye drops, ear drops, and infusion solutions. Due to adverse effects, some representatives had to be withdrawn from the market in the past, for example trovafloxacin and grepafloxacin.
Structure and properties
Quinolones are derivatives of 4-quinolone and of quinoline, which were originally developed starting from antimalarials. All of the newer agents are fluorinated agents known as fluoroquinolones. The first fluorinated quinolone to be developed was norfloxacin in 1978, which was approved in many countries in 1983. Ciprofloxacin also belongs to this group.
Effects
The quinolones (ATC J01MA) have bactericidal properties against Gram-positive and Gram-negative pathogens. The effects are due to inhibition of bacterial DNA replication by inhibition of topoisomerase II (DNA gyrase) and topoisomerase IV.
Indications
For the treatment of bacterial infectious diseases. These include (selection):
- Urinary tract infections
- Respiratory infections
- Infections of the genital tract, gonorrhea
- Gastrointestinal infections
- Infections of the bones and joints
- Anthrax
Dosage
According to the professional information. Use depends on the product. Some quinolones must be taken fasting, that is, at least one hour before or two hours after a meal (e.g., norfloxacin). Others, however, can be administered regardless of meals (e.g., levofloxacin, moxifloxacin).
Active Ingredients
The following drugs are registered in many countries:
- Ciprofloxacin (ciproxin, generic).
- Delafloxacin (Quofenix)
- Levofloxacin (Tavanic, generic).
- Moxifloxacin (Avalox, Vigamox, generics).
- Norfloxacin (Noroxin, generics)
- Ofloxacin (Tarivid, Floxal)
Other representatives exist that are not available in many countries, such as ozenoxacin and numerous others.
Contraindications
Full precautions can be found in the drug label.
Interactions
Some quinolones interact with CYP450 isoenzymes. Ciprofloxacin and norfloxacin are inhibitors of CYP1A2. Absorption of the active ingredients may be reduced with concomitant ingestion of food, other drugs, and multivalent cations (e.g., norfloxacin). Combination with drugs that prolong the QT interval may result in cardiac arrhythmias (e.g., moxifloxacin).
Adverse effects
Possible adverse effects include (selection):
- Central nervous disturbances such as headache, dizziness, sensory disturbances.
- Psychiatric disorders such as depression, suicidal thoughts.
- Gastrointestinal complaints such as diarrhea, abdominal pain, taste disturbances, nausea.
- Skin rash, itching, photosensitivity, hypersensitivity reactions.
- Visual disturbances
- Oral thrush, vaginal fungus
- Prolongation of the QT interval, cardiac arrhythmias.
- Increase in liver enzymes, liver dysfunction, hepatitis.
- Tendinitis and tendon rupture
