A prospective, double-blind, randomized study comparing the efficacy and safety of low-dose ciprofloxacin with ampicillin in the treatment of bronchitis

Characterization of the population pharmacokinetics of ampicillin in neonates using an opportunistic study design

Although ampicillin is the most commonly used drug in neonates, developmental pharmacokinetic (PK) data to guide dosing are lacking. Ampicillin is primarily renally eliminated, and developmental changes are expected to influence PK. We conducted an open-label, multicenter, opportunistic, prospective PK study of ampicillin in neonates stratified by gestational age (GA) (≤ 34 or >34 weeks) and postnatal age (PNA) (≤ 7 or >7 days). Drug concentrations were measured by tandem mass spectrometry. PK data were analyzed using population nonlinear mixed-effects modeling in NONMEM 7.2. Monte Carlo simulations were conducted to determine the probability of target attainment for the time in which the total steady-state ampicillin concentrations remained above the MIC (T>MIC) for 50%, 75%, and 100% of the dosing interval. A total of 142 PK samples from 73 neonates were analyzed (median [range] GA, 36 [24 to 41] weeks; PNA, 5 [0 to 25] days). The median ampicillin dose was 200 (100 to 350) mg/kg/day. Postmenstrual age and serum creatinine were covariates for ampicillin clearance (CL). A simplified dosing regimen of 50 mg/kg every 12 h for GA of ≤ 34 weeks and PNA of ≤ 7 days, 75 mg/kg every 12 h for GA of ≤ 34 weeks and PNA of ≥ 8 and ≤ 28 days, and 50 mg/kg every 8 h for GA of >34 weeks and PNA of ≤ 28 days achieved the prespecified surrogate efficacy target in 90% of simulated subjects. Ampicillin CL was associated with neonatal development. A simplified dosing regimen stratified by GA and PNA achieves the desired surrogate therapeutic target in the vast majority of neonates.

Oral fluoroquinolones in the treatment of pneumonia, bronchitis and sinusitis

BACKGROUND

Despite a relatively large number of clinical studies comparing oral fluoroquinolones to one antibiotic class comparator, there is limited information on the relative efficacy of different fluoroquinolones.

OBJECTIVE

To examine the efficacy and tolerability of oral fluoroquinolones in the treatment of mild to moderate community-acquired pneumonia, acute exacerbations of chronic bronchitis and sinusitis.

METHODS

A systematic review was undertaken with a MEDLINE search for antibiotics and indications. Included studies met the following criteria: original study; random allocation to treatment groups; treatment with one of the following oral antibiotics - moxifloxacin, levofloxacin, ciprofloxacin, gatifloxacin; controlled by either placebo or an active comparator medication; double-blind, single-blind or open treatment; men and women (18 years of age and older); diagnosis of one of the three indications; and treatment duration of at least three days. Outcome measures included efficacy and safety. Comparative and single arm meta-analyses were conducted. Statistical differences in antibiotic success rates were evaluated. Pooled point estimates and 95% CIs for the comparative statistics (z-scores, P-values) and the single-arm analysis were examined to evaluate equivalence.

RESULTS

The results of the comparative and single meta-analyses revealed no major differences between the new fluoroquinolones. This is not surprising because the clinical studies were designed to show equivalence versus their comparators. Few comparative evaluations were conducted due to a paucity of studies. In relation to other competitors, small differences were seen.

CONCLUSIONS

Results indicate that, in general, fluoroquinolones had similar efficacy, overall safety and dropout rates.

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.

Lower respiratory tract infection therapy--the role of ciprofloxacin

Lower respiratory tract infections account for a large proportion of prescribed antibiotics and, with emerging resistance to standard agents, the introduction of the fluoroquinolones, in particular ciprofloxacin, has provided a further component in the armamentarium. This review encompasses 37 published clinical trials which featured ciprofloxacin; 3274 patients with lower respiratory tract infections were treated with this agent; in 94.1% of patients treatment was clinically successful and 90.9% of cases showed eradication of the causative pathogen. When these data were supplemented with previously unpublished information from the clinical trial database, specific organism eradication rates of 86.1%, 96.2% and 94.6% for Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis, respectively, were observed. These findings suggest that the high respiratory tissue penetration of ciprofloxacin and the achievable minimum inhibitory concentrations lead to acceptable clinical outcomes in lower respiratory tract infections.

Use of quinolones for the treatment of acute exacerbations of chronic bronchitis

The availability of a new generation of quinolones expands the choices of antimicrobials for therapy of acute exacerbations of chronic bronchitis. These agents have broad antimicrobial activity, including good in vitro activity against respiratory pathogens, and advantageous pharmacokinetic characteristics, including bronchial tissue penetration. Ciprofloxacin, enoxacin, ofloxacin, and temafloxacin have been evaluated in a number of clinical trials, compared to the reference agents ampicillin, amoxicillin (with and without clavulanate), cefaclor, doxycycline, and erythromycin. Ciprofloxacin, ofloxacin, and temafloxacin have generally demonstrated greater clinical success than enoxacin. While these agents are effective against many respiratory pathogens, Streptococcus pneumoniae and Pseudomonas aeruginosa infections appear to pose problems. Temafloxacin and ciprofloxacin have been compared; temafloxacin eradicated S. pneumoniae more efficiently and did not interact with theophylline. Fluoroquinolones are an important addition to the agents useful for bacterial exacerbations of chronic bronchitis.

Overview of fluoroquinolone safety

The safety of the fluoroquinolone antimicrobial agents is reviewed, discussing documented and potential clinical and laboratory adverse effects and drug-drug interactions. In prospective, randomized, double-blind clinical trials comparing fluoroquinolones to nonquinolone drugs or placebo, the fluoroquinolones were not significantly different (22 studies) or were superior (5 studies) to comparison agents but were only rarely more toxic (2 studies). Adverse effects included mild gastrointestinal toxicities and less common but more problematic central nervous system toxicities. Clinically important interactions occurred with coadministration of antacids and all fluoroquinolones and with theophylline and enoxacin and to a lesser extent ciprofloxacin and pefloxacin but not other fluoroquinolones. Potential adverse effects such as cartilage damage, DNA damage, teratogenicity, and crystalluria, while of concern, have not as yet been shown to be of clinical importance. Therapy of bacterial infections in children and adolescents is relatively contraindicated, but growing clinical experience with treatment of these patients has not so far revealed serious bone or cartilage toxicity. The fluoroquinolones thus far have exhibited a favorable safety profile, but our clinical experience is still limited, and monitoring for as yet unappreciated toxicities is warranted.