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Fluoroquinolones - Antimicrobial Spectrum Fluoroquinolones are broad-spectrum antibiotics. ► They are effective against many different types of bacteria, both Gram-negative including pseudomonas and Gram-positive. Pharmacokinetics: 1- Absorption 1- Absorption. Well absorbed after oral administration (50% to >95%). ► This degree of absorption result in high blood levels comparable to their intravenous preparations. ► Thus, oral preparations should be used if the patient is able to take oral medications. 3
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AntimicrobialsAntimicrobials- Quinolones & Fluoroquinolones- Quinolones & Fluoroquinolones
Pharmacology -1Pharmacology -1 DSX 215DSX 215
Dr/ Abdulaziz SaeedanDr/ Abdulaziz Saeedan Pharmacy CollegePharmacy College
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Quinolones and FluoroquinolonesQuinolones and Fluoroquinolones• The quinolones are a family of synthetic antibiotics.• The parent of this group is nalidixic acidnalidixic acid.• Nalidixic acid Nalidixic acid is a synthetic narrow spectrum antibiotic. ► Active against gram-negative bacteria except pseudomonaspseudomonas species.
• The addition of fluorine atom to the original quinolone antibiotics produced a new class of drugs, the fluoroquinolonesthe fluoroquinolones
• Fluoroquinolones are synthetic broad-spectrum antibiotics.
► Active against gram-negative bacteria, especially pseudomonaspseudomonas species in addition to gram-positive bacteria.
• Due to the excellent activity and safety of fluoroquinolones, they become alternatives to penicillin in the treatment of various infections.
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Fluoroquinolones - Antimicrobial SpectrumFluoroquinolones - Antimicrobial Spectrum
• Fluoroquinolones are broad-spectrum antibiotics.► They are effective against many different types of bacteria, both Gram-negative
including pseudomonas and Gram-positive.
Pharmacokinetics:Pharmacokinetics:1- Absorption1- Absorption.• Well absorbed after oral administration (50% to >95%). ► This degree of absorption result in high blood levels comparable to their
intravenous preparations. ► Thus, oral preparations should be used if the patient is able to take oral
medications.
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2- Distribution2- Distribution.•Distributed into urine, kidney, prostate tissue, lung, stool, skin. ► So fluoroquinolones are very useful for treatment of infections in these areas of the body.
3- Elimination3- Elimination.•The kidneys are an important route of elimination.
Fluoroquinolones – AdvantagesFluoroquinolones – Advantages•Ease of administration•Excellent oral absorption•Prolonged half-lives ► daily or twice daily dosing •Excellent tissue penetration ► widely distributed
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Fluoroquinolones - ClassificationFluoroquinolones - Classification First Generation. ► Nalidixic acid• Antimicrobial Spectrum: Antimicrobial Spectrum: Gram-negative bacteria (but not Pseudomonas species)• Used only for uncomplicated urinary tract infections.• Nalidixic acid require more frequent dosing than the newer quinolones.
Second Generation. ► Norfloxacin, Lomefloxacin, Ciprofloxacin, Ofloxacin• Ciprofloxacin and ofloxacin are the most widely used second-generation quinolones
because of their availability in oral and intravenous formulations• Antimicrobial Spectrum: Antimicrobial Spectrum: Gram-negative bacteria (including Pseudomonas species),
some gram-positive bacteria (including Staphylococcus aureus but not Streptococcus pneumoniae).
• Ciprofloxacin is the most potent fluoroquinolone against Pseudomonas . • Used for uncomplicated and complicated urinary tract infections, pyelonephritis,
prostatitis, skin and soft tissue infections.
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Third Generation. ► Levofloxacin, Gatifloxacin, Sparfloxacin, Moxifloxacin.• Antimicrobial Spectrum: Antimicrobial Spectrum: The same as second-generation agents plus expanded
activity against gram-positive bacteria (Streptococcus pneumoniae).• Used for bronchitis and pneumonia
Fourth Generation. ► Trovafloxacin• Antimicrobial Spectrum: Antimicrobial Spectrum: Same as for third-generation agents plus anaerobic
bacteria.• The same uses of first-, second- and third-generation agents.
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Fluoroquinolones– Action & Mechanism of ActionFluoroquinolones– Action & Mechanism of Action
Action:Quinolones and fluoroquinolones are bacteriocidal drugs, meaning that they kill
bacteria.
MOA:• Quinolones and fluoroquinolones inhibit bacterial DNA-gyrase enzyme which
is necessary for supercoiling and replication of DNA .• This action results in damage of bacterial DNA and bacterial cell death. Thus,
fluoroquinolones are bactericidal agents.
NOTE:• Fluoroquinolones are the only class of antimicrobial agents that are direct
inhibitors of bacterial DNA synthesis. • Gyrase is an essential enzyme in prokaryotes but it is not found in eukaryotes,
So fluoroquinolones do not interfere with human DNA.. 7
Fluoroquinolones - Side Effects/PrecautionsFluoroquinolones - Side Effects/Precautions
1- The most common adverse effects of fluoroquinolones are nausea, vomiting and diarrhea, which occur in 3 -6 % of patients.
2- Other more serious but less common side effects are CNS effects (headache, confusion and dizziness).
3- Fluoroquinolones are not recommended for use in patients younger than 18 years.► They can affect the growth of bones, teeth, and cartilage.
4- Fluoroquinolones are not recommended for pregnant or feeding women. ► They have the potential to cause embryocidal effects. ► These agents are also excreted in breast milk.
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Fluoroquinolones -Fluoroquinolones - indicationsindications
• All of the fluoroquinolones are effective in treating urinary tract infections caused by susceptible organisms.
• Prostatitis ► They are the first-line treatment of uncomplicated or complicated cystitis.• Lower respiratory tract infections ► bronchitis, pneumonia • Acute sinusitis • Diarrhoea due to E.coli, Salmonellosis, Shiegellae,• Skin and soft tissue infections
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