Introduction
Ciprofloxacin is a second generation fluoroquinolone that has spawned many derivative antibiotics. It is formulated for oral, intravenous, intratympanic, ophthalmic, and otic administration for a number of bacterial infections.
Uses
Ciprofloxacin is a second generation fluoroquinolone used to treat various susceptible bacterial infections.
Ciprofloxacin is only indicated in infections caused by susceptible bacteria.
Ciprofloxacin immediate release tablets, oral suspensions, and intravenous injections are indicated for the treatment of skin and skin structure infections, bone and joint infections, complicated intra-abdominal infections, nosocomial pneumonia, febrile neutropenia, adults who have inhaled anthrax, plague, chronic bacterial prostatitis, lower respiratory tract infections including acute exacerbations of chronic bronchitis, urinary tract infections, complicated urinary tract infections in pediatrics, complicated pyelonephritis in pediatrics, and acute sinusitis.
A ciprofloxacin otic solution and otic suspension with hydrocortisone are indicated for acute otitis externa. Ciprofloxacin suspension with dexamethasone is indicated for acute otitis media in pediatric patients with tympanostomy tubes or acute otitis externa. A ciprofloxacin intratympanic injection is indicated for pediatric patients with bilateral otitis media with effusion who are having tympanostomy tubes placed or pediatric patients 6 months or older with acute otitis externa.
A ciprofloxacin eye drop is indicated for bacterial corneal ulcers and conjunctivitis. A ciprofloxacin eye ointment is indicated for bacterial conjunctivitis.
A ciprofloxacin extended release tablet is indicated for uncomplicated urinary tract infections, complicated urinary tract infections, and acute uncomplicated pyelonephritis.
Associated Conditions
Pharmacodynamics
Ciprofloxacin is a second generation fluoroquinolone that is active against many Gram negative and Gram positive bacteria. It produces its action through inhibition of bacterial DNA gyrase and topoisomerase IV. Ciprofloxacin binds to bacterial DNA gyrase with 100 times the affinity of mammalian DNA gyrase. There is no cross resistance between fluoroquinolones and other classes of antibiotics, so it may be of clinical value when other antibiotics are no longer effective. Ciprofloxain and its derivatives are also being investigated for its action against malaria, cancers, and AIDS.
Mechanism of Action
Ciprofloxacin acts on bacterial topoisomerase II (DNA gyrase) and topoisomerase IV. Ciprofloxacin's targeting of the alpha subunits of DNA gyrase prevents it from supercoiling the bacterial DNA which prevents DNA replication.
Absorption
A 250mg oral dose of ciprofloxacin reaches an average maximum concentration of 0.94mg/L in 0.81 hours with an average area under the curve of 1.013L/h*kg. The FDA reports an oral bioavailability of 70-80% while other studies report it to be approximately 60%. An early review of ciprofloxacin reported an oral bioavailability of 64-85% but recommends 70% for all practical uses.
Volume of Distribution
Cirpofloxacin follws a 3 compartment distribution model with a central compartment volume of 0.161L/kg and a total volume of distribution of 2.00-3.04L/kg.
Protein Binding
20-40%.
Route of Elimination
27% of an oral dose was recovered unmetabolized in urine compared to 46% of an intravenous dose. Collection of radiolabelled ciprofloxacin resulted in 45% recovery in urine and 62% recovery in feces.
Half Life
The average half life following a 250mg oral dose was 4.71 hours and 3.65 hours following a 100mg intravenous dose. Generally the half life is reported as 4 hours.
Clearance
The average renal clearance after a 250mg oral dose is 5.08mL/min*kg. Following a 100mg intravenous dose, the average total clearance is 9.62mL/min*kg, average renal clearance is 4.42mL/min*kg, and average non renal clearance is 5.21mL/min*kg.
Toxicity
Patients experiencing an overdose may present with nausea, vomiting, abdominal pain, crystalluria, nephrotoxicity, and oliguria. Ciprofloxacin overdose typically leads to acute renal failure. An overdose may progress over the next 6 days with rising serum creatinine and BUN, as well as anuria. Patients may require prednisone therapy, urgent hemodialysis, or supportive therapy. Depending on the degree of overdose, patients may recover normal kidney function or progress to chronic kidney failure.
The oral LD50 in rats is >2000mg/kg.
Ciprofloxacin for intratympanic injection or otic use has low systemic absorption and so it unlikely to be a risk in pregnancy or lactation. There is generally no harm to the fetus in animal studies, however high doses may lead to gastrointestinal disturbances in the mother which may increase the incidence of abortion. In human studies there was no increase in fetal malformations above background rates. The risk and benefit of ciprofloxacin should be weighed in pregnancy and breast feeding.
2/8 in vitro tests and 0/3 in vivo tests of mutagenicity of ciprofloxacin have yielded a positive result.
Oral doses of 200 and 300 times the maximum recommended clinical dose in rats and mice have shown no carcinogenicity or tumorigenicity.
Oral doses above the maximum recommended clinical dose have shown no effects on fertility in rats.
Food Interactions
- Avoid milk and dairy products. Dairy products and calcium fortified juices decrease the absorption of ciprofloxacin.
- Limit caffeine intake.
- Take with or without food. The absorption is not significantly affected by food.
Dosage
Adults: The dosage range for adults is 100-750 mg twice daily.
In infections of the lower and upper urinary tract (depending on severity): 250-500 mg twice daily.
In respiratory tract infections: 250-500mg twice daily for both upper and lower respiratory tract infections, depending on the severity. For the treatment of known Streptococcus pneumonia infection, the recommended dosage is 750 mg twice daily.
In gonorrhea: A single dose of 250 or 500 mg.
In the majority other infections: 500-750 mg twice daily should be administered.
Cystic fibrosis: In adults with pseudomonal infections of the lower respiratory tract , the normal dose is 750 mg twice daily. As the pharmacokinetics of Ciprofloxacin remain unchanged in patients with cystic fibrosis, the low body weight of these patients would be fallen into consideration when determining dosage.
Impaired renal function: Dosage adjustment is not usually required except in patients with several renal impairment. (serum creatinine >265 micro mol/l or creatinine clearance <20 ml/minute). If adjustment is necessary, this may be achieved by reducing the total daily dose by half, although monitoring of drug serum levels provide the most reliable basis for dose adjustment.
Elderly: Although higher Ciprofloxacin serum levels are found in the elderly, no adjustment of dosage is necessary.
Adeloscents and children: As with other drugs in its class, Ciprofloxacin has been shown to cause arthropathy in weight bearing joints of immature animals. Although the relevance of this to man is unknown, its use in children, growing children and growing adolescents is not recommended. However, where the benefit of using Ciprofloxacin is considered to outweigh the potential risk, the dosage should be 7.5-15 mg/kg/day depending upon the severity of infection, administered in two divided doses.
Duration of treatment: The duration of treatment depends upon the severity of infection, clinical response and bacteriological findings.
For acute infections: The usual treatment period is 5 to 10 days with Ciprofloxacin tablets. Generally treatment should be continued for three days after the signs and symptoms of the infection have disappeared.
Extended-release tablet:
- In uncomplicated urinary tract infection (acute cystitis), the recommended dose of extended-release tablet is 1000 mg tablet once daily for three days.
- Urinary Tract Infection: Mild to Moderate: 200 mg 12 hourly for 7-14 days; Severe or Complicated: 400 mg 12 hourly for 7-14 days
- Lower Respiratory Tract infection: Mild to Moderate: 400 mg 12 hourly for 7-14 days; Severe or Complicated: 400 mg 8 hourly for 7-14 days
- Nosocomial Pneumonia: Mild/Moderate/Severe: 400 mg 8 hourly for 10-14 days
- Skin and Skin Structure: Mild to Moderate: 400 mg 12 hourly for 7-14 days; Severe or Complicated: 400 mg 8 hourly for 7-14 days
- Bone and Joint Infection: Mild to Moderate: 400 mg 12 hourly for more than 4-6 weeks; Severe/Complicated: 400 mg 8 hourly for more than 4-6weeks
- Intraabdominal (Acute abdomen): Complicated: 400 mg 12 hourly for 7-14 days
- Acute Sinusitis: Mild/Moderate: 400 mg 12 hourly for 10 days
- Chronic Bacterial Prostatitis: Mild/Moderate: 400 mg 12 hourly for 28 Days.
