Fluoroquinolones are a class of broad-spectrum antibiotics that include ciprofloxacin, moxifloxacin, and norfloxacin. They work by inhibiting bacterial DNA synthesis through effects on DNA gyrase and topoisomerase IV. Ciprofloxacin is an example that is administered orally or intravenously to treat various bacterial infections. However, bacterial resistance to fluoroquinolones has been increasing worldwide. Ciprofloxacin specifically has good oral absorption and bioavailability but can interact with various other drugs if not taken correctly. It is also important to monitor for potential side effects like gastrointestinal issues, rashes, and neurotoxicity with ciprofloxacin use.

1. CIPROFLOXACIN
“Success In Life Is A Result Of Decision. Failure In
Life Is A Result Of Decision”
Group: WinnerzKlub Inc.
Year: 2019

2. What are Fluoroquinolones?
 The fluoroquinolones are synthetic, broad-
spectrum agents with bactericidal activity.
 Examples include: ciprofloxacin,
moxifloxacin, & norfloxacin & ofloxacin.
 The newer oral quinolones provide an
alternative to β-lactams in the treatment of
community acquired lower respiratory
infections.
 Related structurally to Nalidixic acid.

3. (cont’d):
 Inhibitors of bacterial DNA synthesis-
quinolones
◦ Inhibits cytochrome P450 (CYP₁A₂)
 Unfortunately, bacterial resistance to
quinolones is increasing world-wide, &
appropriate use is needed to extend
their clinical use.

4. Bacterial resistance:
Year Resistance
1987 Ciprofloxacin-resistant Escherichia coli (30-40%)
2007/2008 Ciprofloxacin-resistant Neisseria meningitidis reported in
USA
•Enterobacteria
•Salmonella spp
•Staphylococcus aureus
•Vibrio cholerae

5. Ciprofloxacin:
 Is an example of a fluoroquinolone.
 Is not ototoxic.
 Ciprofloxacin & moxifloxacin are the
only quinolones available for
parenteral use.
 Used in ocular infections.
 Metabolized in liver and highly
dependent on kidneys for excretion.

6. Mechanism of action:
 Interfere with bacterial topoisomerase
II (DNA gyrase) & topoisomerase IV.
◦ the enzymes involved in the supercoiling
of DNA that is necessary for the
duplication, transcription & repair of
bacterial DNA.

7. PARAMETERS:
 Oral bioavailability is 50-70%.
 Half-life: 4hours
 May be used for lower UTIs.
 Usually administered in dosage of
500ml twice daily.
 NB: Avoid in childhood and pregnancy
& in pts. taking corticosteroids.
◦ Should not be used in pts. with tendonitis.

8. ACTIONS:
 Ciprofloxacin ear drops (0.3%) & eye
drops for severe conjunctivitis & bacterial
keratitis.
 Useful in gram (-)ve septicaemia, skin &
bone infections, urinary & respiratory
tract infections, some sexually
transmitted diseases such as gonorrhea
& in severe cases of travelers' diarrhea.
 As alternative (single dose) in
meningococcal meningitis

9. DRUG INTERACTIONS:
DRUG POSSIBLE EFFECTS & MANAGEMENT
Antacids,
ferrous sulfate
or sucralfate
May decrease absorption of ciprofloxacin, reducing
drug effectiveness. Administer quinolone at least 2hrs
before these medications.
Theophylline &
other xanthines
Ciprofloxacin & norfloxacin may inhibit the
theophylline metabolism, resulting in increased
theophylline plasma concentration & toxicity. Monitor
theophylline plasma concentration closely, as dosage
adjustments may be required.
Thyroxine Decreases absorption of thyroxine from GIT. A 4hrs
interval with administration of thyroxine.
Iron Forms complexes with iron, reducing overall
bioavailability

10. Side Effects:
 Gastric disturbances
 Photosensitive rashes
 Occasional neurotoxicity

11. Sa Oji:
 Sources:
◦ Pharmacology for Health Professionals,
4th Ed., B.Bryant & K.Knights.
◦ Clinical Medicine, 8th Ed., Kumar and
Clarks.