Lower respiratory tract infection therapy--the role of ciprofloxacin

Therapeutic advances of new fluoroquinolones

Fluoroquinolone antimicrobials have been available for over 10 years. Recent modifications to nuclear side-chains have enhanced both the antimicrobial and pharmacokinetic profiles of this class. Rapidly increasing antimicrobial resistance among community and hospital bacterial pathogens has diminished therapeutic options. Infections caused by such pathogens, including drug-resistant Streptococcus pneumoniae and multi-resistant Enterobacteriaceae are now treatable by few classes of antibacterials, one of these being the fluoroquinolones. Ciprofloxacin was one of the first effective agents available in both iv. and oral formulations for the treatment of Gram-negative infection, resistant to other antibiotics. More recent developments, such as sparfloxacin and grepafloxacin, are more effective in vitro against Gram-positive pathogens, although their safety profile may be less promising. Fluoroquinolones not yet in widespread clinical use, including trovafloxacin, clinafloxacin and moxifloxacin, hold considerable promise as community 'respiratory antimicrobials' and the results of clinical trials are awaited with anticipation. In this review, the three generations of fluoroquinolone development are examined and the relative antimicrobial, pharmacokinetic, clinical and safety profiles of available and developmental quinolones are compared.

Maintaining fluoroquinolone class efficacy: review of influencing factors

Previous experience with antimicrobial resistance has emphasized the importance of appropriate stewardship of these pharmacotherapeutic agents. The introduction of fluoroquinolones provided potent new drugs directed primarily against gram-negative pathogens, while the newer members of this class demonstrate more activity against gram-positive species, including Streptococcus pneumoniae. Although these agents are clinically effective against a broad range of infectious agents, emergence of resistance and associated clinical failures have prompted reexamination of their use. Appropriate use revolves around two key objectives: 1) only prescribing antimicrobial therapy when it is beneficial and 2) using the agents with optimal activity against the expected pathogens. Pharmacodynamic principles and properties can be applied to achieve the latter objective when prescribing agents belonging to the fluoroquinolone class. A focused approach emphasizing "correct-spectrum" coverage may reduce development of antimicrobial resistance and maintain class efficacy.

Community-acquired lower respiratory tract infections: etiology and treatment

The current therapy for community-acquired lower respiratory tract infections is often empiric, usually involving administration of a beta-lactam or macrolide. However, the increasing prevalence of antibiotic resistance in frequently isolated respiratory tract pathogens has complicated the antimicrobial selection process. This review will discuss the incidence of various respiratory pathogens, as well as update the clinician on the various antimicrobial alternatives available, with particular emphasis on the role of the newer fluoroquinolones in the treatment of acute exacerbations of chronic bronchitis and community-acquired pneumonia.

Randomized, double-blind study comparing 5- and 7-day regimens of oral levofloxacin in patients with acute exacerbation of chronic bronchitis

A randomized, double-blind, multicentre study was conducted in adult patients with acute exacerbation of chronic bronchitis (AECB), to compare the efficacy of a 5-day course of levofloxacin 500 mg once daily, with the standard 7-day regimen at the same dose. Five hundred and thirty-two patients from 48 centres in 10 countries were randomized to receive levofloxacin: 268 and 264 received the 5- and 7-day courses, respectively. The primary efficacy analysis was the clinical response at 7-10 days post-treatment in the per-protocol (PP) population. Clinical success rates in the primary PP analysis of 482 patients were 82.8% (197/238) for the 5-day group and 84.8% (207/244) for the 7-day group. The difference in success rates was -2.1% with a 95% CI of (-9.1 to 4.9%). The bacteriological response showed eradication rates of 82.1% (92/112) and 83.2% (84/101) in the 5- and 7-day groups, respectively. Both treatments were well tolerated. These results show that for patients with AECB levofloxacin 500 mg once daily for 5 days provides equivalent clinical and bacteriological success to the same dose given for 7 days irrespective of the patient's age, the frequency of exacerbations or the presence of co-existing cardiopulmonary or chronic obstructive airways disease.

The Role of Quinolones in Upper Respiratory Tract Infections

Fluoroquinolones are widely used in clinical practice because of their advanced pharmacokinetic properties, potential activity against most bacterial species, excellent clinical responses, and few side effects. Quinolones have no role in the treatment of pharyngitis or simple otitis media. Until recently, the available fluoroquinolones were not indicated for the treatment of acute purulent sinusitis because of their perceived inactivity against Streptococcus pneumoniae. Although not generally considered to be drugs of first choice, older quinolones have efficacy similar to that of cephalosporins and b-lactams in randomized clinical trials. Well-conducted clinical trials have shown that the new fluoroquinolones are as effective as standard comparators in patients with suspected or proven acute bacterial sinusitis and may allow shorter treatment. Ciprofloxacin remains the fluoroquinolone of choice for chronic otitis media and malignant otitis media. The new "respiratory" fluoroquinolones have microbiologic and pharmacokinetic advantages over the older agents. Clinical trials have confirmed clinical activity, but superiority compared with older agents has not been conclusively shown. Trials devised to demonstrate clinical or pharmacoeconomic benefits are still required.

The efficacy, safety and pharmacokinetics of intravenous ciprofloxacin in patients with lower respiratory tract infections

The efficacy and safety of intravenous ciprofloxacin 200 mg every 8 or 12 h and 300 mg every 12 h in treatment lasting 3-14 days were investigated in patients with lower respiratory tract bacterial infections. Patients presented with pneumonia, bronchiectasis with infection, previous pulmonary tuberculosis with infection and diffuse panbronchiolitis. Clinical efficacy was seen in six of eight patients, with apparent recovery in terms of chest radiographs, fever reduction and laboratory findings. Pharmacokinetic analysis in one patient treated with intravenous ciprofloxacin 300 mg showed that at 0.5 h after the first dose, ciprofloxacin serum and sputum concentrations were equivalent (2.45 micrograms/ml and 2.25 micrograms/ml, respectively). Adverse events were recorded in only two patients and involved a slight elevation in liver function tests and eosinophilia. This study indicates that intravenous ciprofloxacin is useful in the treatment of lower respiratory tract infections.

New Fluoroquinolones: Real and Potential Roles

The second-generation fluoroquinolones have enjoyed successful clinical use for more than 10 years in many countries, and they have a valued and proven record of safety and efficacy. However, deficiencies with respect to gram-positive and anaerobic organisms limit the use of these agents in respiratory, intra-abdominal, and pelvic infections. New, third-generation agents with dramatically increased activity against gram-positive and anaerobic bacteria--notably, Streptococcus pneumoniae and Bacteroides fragilis--have shown high rates of efficacy in pneumonia, bronchitis, and surgical and gynecologic infections. Although most of these new drugs produce similar clinical results, adverse reaction profiles differ and may influence therapeutic choices.

Therapy for pneumococcal infection at the millennium: doubts and certainties

Rapidly burgeoning worldwide multiple drug-resistant pneumococcal serotypes pose an urgent demand for new management approaches. Perhaps modern intensive care methods may have alternatives to offer. Indeed, standard assessments such as the admission APACHE II score may overestimate individual risk of death in severe CAP, and mortality can be reduced. However, among those at highest risk for mortality in the early phase of invasive disease, the conclusions reached 2-3 decades ago, that it is questionable whether a more effective drug than penicillin can be developed, and that a reduction in the number of deaths consequent to this infection can be accomplished only by widespread immunoprophylactic measures, remain inescapable. Clearly, as discussed elsewhere in this supplement, the continuing validity of these 20-year-old conclusions and the global prevalence of DRSP demand the development and marketing of new conjugate vaccines, although more widespread use of the existing 23-valent polysaccharide vaccine among high-risk populations is essential in the interim. With respect to resistance selection pressures, antibiotic prescription control may provide the answer. However, patient expectations of antibiotic therapy for trivial respiratory infection is high and, in the United Kingdom, 75% of previously healthy adults will receive it; those who do not will usually consult another physician in an effort to secure such therapy. Thus, without the intervention of government or managed care organizations, self-regulation in prescribing is unlikely. The evidence for beta-lactam treatment failure in meningitis has led to alternative approaches, with vancomycin as the primary agent. Penicillins may remain effective for otitis media, but oral cephalosporins are suspect. Data on pediatric pneumococcal pneumonia continue to suggest use of beta-lactams, at least for disease caused by strains with intermediate penicillin sensitivity. Pallares et al concluded that penicillins and cephalosporins remain the drugs of choice for severe pneumococcal pneumonia in adults. Others who share this conclusion often cite that study as evidence. However, in the case of penicillins, the mortality rate was 6% higher in a subgroup selected for monomicrobial infection and reduced risk factors for mortality when penicillin-resistant infection was present, and the overall mortality was 14% higher with penicillin-resistant strains (taking into account "all comers"). Those who depend on the findings of evidence-based medicine may accept the premise that penicillins and cephalosporins remain the drugs of choice, and agree with Goldstein and Garau that it would indeed be a mistake to adopt alternative therapies. Others may consider the deaths of 6 of 100 patients who were not in the highest-risk group too high a price to pay for statistical significance and may be skeptical of the continued use of beta-lactam therapy on higher-risk patients. In addition, the persistent selection pressure applied by continued use of beta-lactams offers a powerful population-based argument for alternatives. As DRSP continues to spread and resistant strains with penicillin MIC >2 mg/L become more prevalent, new agents such as the azabicyclo-methoxyquinolone, moxifloxacin, and perhaps grepafloxacin, but not the more toxic sparfloxacin and trovafloxacin, will undoubtedly flourish as treatments for CAP. By that time, the results of clinical studies on ketolides and oxazolidinones could offer further choices.

The efficacy and safety of a new ciprofloxacin suspension compared with co-amoxiclav tablets in the treatment of acute exacerbations of chronic bronchitis

A multinational, multicentre, randomized, prospective, parallel-group study compared treatment with ciprofloxacin administered as an oral suspension (500 mg twice daily for 7 days) with co-amoxiclav tablets (625 mg three times daily for 7 days) in patients suffering from acute exacerbations of chronic bronchitis (AECB). A total of 147 of 165 cases treated with ciprofloxacin (89.1%) and 146 of 162 cases treated with co-amoxiclav (90.1%) were classified as being clinical successes at the primary efficacy assessment 7 days after the end of therapy (assessed as reduced cough, improvement in dyspnoea, reduction in 24-h sputum volume or reduced purulence of sputum). Treatment equivalence was statistically confirmed; treatment difference:--1.0%, 95% CI--6.6% and 4.5%. Before treatment, 128 bacterial strains were isolated from 103 patients (60 ciprofloxacin and 68 co-amoxiclav). The most commonly isolated organism was Haemophilus influenzae (60 isolates), followed by Moraxella catarrhalis (12 isolates), Streptococcus pneumoniae (11 isolates) and Staphylococcus aureus (10 isolates). At day 14, 40 of 46 ciprofloxacin-treated patients (87.0%) and 46 of 55 co-amoxiclav-treated patients (83.6%) who were valid for bacteriological analysis were classified as being bacteriological success (classed as eradication, eradication with colonization or presumed eradication; treatment difference: 3.3%, 95% CI--8.3% and 14.9%). The adverse event profile was comparable between treatment groups. Most adverse events considered possibly or probably related to study drug were related to the gastrointestinal system and were of mild or moderate severity: nausea (13% ciprofloxacin, 10.6% co-amoxiclav), flatulence (10.3% ciprofloxacin, 3.9% co-amoxiclav), abdominal pain (7.6% ciprofloxacin, 7.3% co-amoxiclav) and diarrhoea (4.3% ciprofloxacin, 6.7% co-amoxiclav). We concluded that a 7-day course of ciprofloxacin suspension is equivalent to a 7-day course of co-amoxiclav tablets in terms of clinical and bacteriological efficacy and tolerability for the treatment of AECB. Thus, ciprofloxacin suspension may offer a suitable alternative treatment for AECB patients who have difficulty in swallowing, or who prefer liquid medications to tablets.

Efficacy and safety of high dose intravenous ciprofloxacin in the treatment of bacterial pneumonia. Italian Ciprofloxacin Study Group

One hundred and fifty three hospitalized patients were enrolled in an open, prospective, multi-center study on the efficacy and safety of intravenous ciprofloxacin (400 mg i.v., b.i.d.) for acute bacterial pneumonia: 93 (63%) patients were valid for efficacy out of 148 valid for intention-to-treat analysis. The most commonly isolated organisms from 93 valid-for-efficacy patients were Pseudomonas aeruginosa (17%), Haemophilus influenzae and parainfluenzae (17%), Streptococcus aureus (14%) and Streptococcus pneumoniae (11%). Cure was achieved in 89/93 (95.7%) valid-for-efficacy patients; effective eradications were obtained in 42 (45%) and presumed eradications in 48 (52%) of the 93 patients. Mild or moderate adverse events (AE) occurred in 13/153 (8.5%) patients assessable for safety; all but one AE were rapidly reversible and only one treatment-stop (0.65%) was decided. The treatment of acute bacterial pneumonias with high-dose parenteral ciprofloxacin appears to be efficacious and well tolerated.

Strategies and options for minimizing resistance emergence in pulmonary infections

The early-onset hospital pulmonary gram-negative infections may respond to ciprofloxacin and co-amoxiclav without significant resistance development. Penicillin-resistant Streptococcus pneumoniae may be treated with macrolides, fluoroquinolones, and glycopeptides. The late-onset hospital pathogens all seem to have developed resistance to cephalosporins, so greater reliance is now made on the fluoroquinolones and carbapenems when aminoglycoside therapy is considered undesirable.

A 1-year community-based health economic study of ciprofloxacin vs usual antibiotic treatment in acute exacerbations of chronic bronchitis: the Canadian Ciprofloxacin Health Economic Study Group

OBJECTIVE

To evaluate the costs, consequences, effectiveness, and safety of ciprofloxacin vs standard antibiotic care in patients with an initial acute exacerbation of chronic bronchitis (AECB) as well as recurrent AECBs over a 1-year period.

DESIGN

Randomized, multicenter, parallel-group, open-label study.

SETTING

Outpatient general practice.

PATIENTS

A total of 240 patients, 18 years or older with chronic bronchitis, with a history of frequent exacerbations (three or more in the past year) presenting with a type 1 or 2 AECB (two or more of increased dyspnea, increased sputum volume, or sputum purulence).

MAIN OUTCOME MEASURES

The assessment included AECB symptoms, antibiotics prescribed, concomitant medications, adverse events, hospitalizations, emergency department visits, outpatient resources such as diagnostic tests, procedures, and patient and caregiver out-of-pocket expenses. Patients completed the Nottingham Health Profile, St. George's Respiratory Questionnaire, and the Health Utilities Index. The parameters were recorded with each AECB and at regular quarterly intervals for 1 year. These variables were compared between the ciprofloxacin-treated group and the usual-care-treated group.

RESULTS

Patients receiving ciprofloxacin experienced a median of two AECBs per patient compared to a median of three AECBs per patient receiving usual care. The mean annualized total number of AECB-symptom days was 42.9+/-2.8 in the ciprofloxacin arm compared to 45.6+/-3.0 days in the usual-care arm (p=0.50). The overall duration of the average AECB was 15.2+/-0.6 days for the ciprofloxacin arm compared to 16.3+/-0.6 days for the usual-care arm. Treatment with ciprofloxacin tended to accelerate the resolution of all AECBs compared to usual care (relative risk=1.20; 95% confidence interval [CI], 0.91 to 1.58; p=0.19). Treatment assignment did not affect the interexacerbation period but a history of severe bronchitis, prolonged chronic bronchitis, and an increased number of AECBs in the past year were associated with shorter exacerbations-free periods. There was a slight, but not statistically significant, improvement in all quality of life measures with ciprofloxacin over usual care. The only factors predictive of hospitalization were duration of chronic bronchitis (odds ratio=4.6; 95% CI, 1.6, 13.0) and severity of chronic bronchitis (odds ratio=4.3; 95% CI, 0.8, 24.6). The incremental cost difference of $578 Canadian in favor of usual care was not significant (95% CI, -$778, $1,932). The cost for the ciprofloxacin arm over the usual care arm was $18,588 Canadian per quality-adjusted life year gained. When the simple base case analysis was expanded to examine the effect of risk stratification, the presence of moderate or severe bronchitis and at least four AECBs in the previous year changed the economic and clinical analysis to one favorable to ciprofloxacin with the ciprofloxacin-treated group having a better clinical outcome at lower cost ("win-win" scenario).

CONCLUSIONS

Treatment with ciprofloxacin tended to accelerate the resolution of all AECBs compared to usual care; however, the difference was not statistically significant. Further, usual care was found to be more reflective of best available care rather than usual first-line agents such as amoxicillin, tetracycline, or trimethoprim-sulfamethoxazole as originally expected. Despite the similar antimicrobial activities and broad-spectrum coverage of both ciprofloxacin and usual care, the trends in clinical outcomes and all quality of life measurements favor ciprofloxacin. In patients suffering from an AECB with a history of moderate to severe chronic bronchitis and at least four AECBs in the previous year, ciprofloxacin treatment offered substantial clinical and economic benefits. In these patients, ciprofloxacin may be the preferred first antimicrobial choice.

Efficacy and tolerability of twice-daily ciprofloxacin 750 mg in the treatment of patients with acute exacerbations of chronic bronchitis and pneumonia

In a review of the US Bayer ciprofloxacin (CIP) database, an analysis was undertaken to summarize the effectiveness and tolerability of CIP 750 mg BID in the treatment of patients with acute exacerbations of chronic bronchitis (AECB) and pneumonia. In five controlled studies, comparator (COMP) agents included ampicillin, intravenous cefuroxime/cefaclor, and other unspecified agents. Primary efficacy end points were clinical success (resolution plus improvement) and bacteriologic eradication at the end of therapy. The incidence of adverse events for CIP 750 mg BID was compared with that for COMP and with that in the CIP 500-mg-BID AECB and pneumonia clinical trials database. In five uncontrolled studies, 443 patients received CIP 750 mg BID; in 5 controlled trials comprising 344 patients, 169 received CIP 750 mg BID and 175 received COMP. Clinical success for CIP was 93% (368/396) and 99% (160/162), respectively, in the uncontrolled and controlled studies versus 98% (156/160) for COMP agents. Corresponding bacteriologic eradication rates for CIP 750-mg-BID-treated patients were 77% (273/356) and 95% (122/128), respectively, and 77% (96/125) for COMP agents. Overall bacteriologic eradication by organism for CIP 750 mg BID included Streptococcus pneumoniae 96% (51/53), Haemophilus influenzae 98% (92/94), Haemophilus parainfluenzae 100% (56/56), Moraxella catarrhalis 100% (14/14; 13 of 14 organisms were isolated in patients with AECB), and Pseudomonas aeruginosa 66% (135/204). Drug-related adverse events were reported in 113 (26%) CIP 750-mg-BID-treated patients in uncontrolled trials and in 62 (37%) CIP 750-mg-BID- and 61 (35%) COMP-treated patients in controlled trials. In the combined data from the CIP 750-mg-BID uncontrolled and controlled trials, adverse events occurred with similar frequency compared with COMP except for nausea (CIP 10%, COMP 7%) and diarrhea (CIP 3%, COMP 13%). In conclusion, CIP 750 mg BID provided excellent clinical success rates in the treatment of patients with AECB and pneumonia. CIP 750 mg BID was well tolerated compared with the COMP agents administered.

Switch therapy: the theory and practice of early change from parenteral to non-parenteral antibiotic administration

OBJECTIVE: The idea behind switch therapy is that antibiotic treatment should be changed from the parenteral to another suitable route (usually oral) as soon as the patient's condition allows. This option is cost-effective in terms of both acquisition costs (oral antibiotics are less expensive than their parenteral counterparts) and indirect costs, and patients may be discharged home sooner. This not only releases hospital beds but is also popular with patients and has other advantages. There are relatively few formal clinical trials, most often using oral third-generation cephalosporins and fluoroquinolones; these agents at present seem the most appropriate to use after parenteral antibiotics have been stopped (usually after 2 to 3 days). Logistic aspects are important, and close collaboration is required between pharmacists, physicians and microbiologists. Further trials are needed in specific patient groups and with other antibiotic regimens to validate the efficacy of switch therapy.

Ciprofloxacin. An updated review of its pharmacology, therapeutic efficacy and tolerability

Ciprofloxacin is a broad spectrum fluoroquinolone antibacterial agent. Since its introduction in the 1980s, most Gram-negative bacteria have remained highly susceptible to this agent in vitro; Gram-positive bacteria are generally susceptible or moderately susceptible. Ciprofloxacin attains therapeutic concentrations in most tissues and body fluids. The results of clinical trials with ciprofloxacin have confirmed its clinical efficacy and low potential for adverse effects. Ciprofloxacin is effective in the treatment of a wide variety of infections, particularly those caused by Gram-negative pathogens. These include complicated urinary tract infections, sexually transmitted diseases (gonorrhoea and chancroid), skin and bone infections, gastrointestinal infections caused by multiresistant organisms, lower respiratory tract infections (including those in patients with cystic fibrosis), febrile neutropenia (combined with an agent which possesses good activity against Gram-positive bacteria), intra-abdominal infections (combined with an antianaerobic agent) and malignant external otitis. Ciprofloxacin should not be considered a first-line empirical therapy for respiratory tract infections if penicillin-susceptible Streptococcus pneumoniae is the primary pathogen; however, it is an appropriate treatment option in patients with mixed infections (where S. pneumoniae may or may not be present) or in patients with predisposing factors for Gram-negative infections. Clinically important drug interactions involving ciprofloxacin are well documented and avoidable with conscientious prescribing. Recommended dosage adjustments in patients with impaired renal function vary between countries; major adjustments are not required until the estimated creatinine clearance is < 30 ml/min/1.73m2 (or when the serum creatinine level is > or = 2 mg/dl). Ciprofloxacin is one of the few broad spectrum antibacterials available in both intravenous and oral formulations. In this respect, it offers the potential for cost savings with sequential intravenous and oral therapy in appropriately selected patients and may allow early discharge from hospital in some instances. In conclusion, ciprofloxacin has retained its excellent activity against most Gram-negative bacteria, and fulfilled its potential as an important antibacterial drug in the treatment of a wide range of infections. Rational prescribing will help to ensure the continued clinical usefulness of this valuable antimicrobial drug.