Cefdinir

Publisher Website
Google Scholar
Abstract
Cefdinir (Omnicef®) is an oral third-generation cephalosporin with good in vitro activity against many pathogens commonly causative in community-acquired infections. The drug provides good coverage against Haemophilus influenzae, Moraxella catarrhalis and penicillin-susceptible Streptococcus pneumoniae, the most common respiratory tract pathogens. Cefdinir is stable to hydrolysis by commonly occurring plasmid-mediated β-lactamases and retains good activity against β-lactamase-producing strains of H. influenzae and M. catarrhalis. The drug distributes into various tissues (e.g. sinus and tonsil) and fluids (e.g. middle ear), and has a pharmacokinetic profile that allows for once-or twice-daily administration. Cefdinir, administered for 5 or 10 days, has shown good clinical and bacteriological efficacy in the treatment of a wide range of mild-to-moderate infections of the respiratory tract and skin in adults, adolescents and paediatric patients in randomised, controlled trials. In adults and adolescents, cefdinir is an effective treatment for both lower (acute bacterial exacerbations of chronic bronchitis [ABECB], communityacquired pneumonia) and upper (acute bacterial rhinosinusitis, streptococcal pharyngitis) respiratory tract infections, and uncomplicated skin infections. Its bacteriological and clinical efficacy in patients with lower respiratory tract infections was equivalent to that of comparator agents (cefprozil [bacteriological only], loracarbef, cefuroxime axetil and cefaclor). In one trial in patients with ABECB, cefdinir produced a higher rate of clinical cure than cefprozil (95% CIs indicated nonequivalence). Cefdinir also produced good clinical and bacteriological responses equivalent to responses with amoxicillin/clavulanic acid in patients with acute bacterial rhinosinusitis. In addition, it was at least as effective as penicillin V (phenoxymethylpenicillin) in streptococcal pharyngitis/tonsillitis and as effective as cefalexin in uncomplicated skin infections. In paediatric patients aged ≥6 months, cefdinir showed similar efficacy to that of amoxicillin/clavulanic acid or cefprozil in acute otitis media, and cefalexin in uncomplicated skin infections. Cefdinir given for 5 or 10 days was at least as effective as penicillin V for 10 days in patients with streptococcal pharyngitis/ tonsillitis. Cefdinir is usually well tolerated. Diarrhoea was the most common adverse event in trials in all age groups. Although the incidence of diarrhoea in cefdinir recipients was generally higher than in adults and adolescents treated with comparators, discontinuation rates due to adverse events were generally similar for cefdinir and comparator groups. In conclusion, cefdinir is a third-generation cephalosporin with a broad spectrum of antibacterial activity encompassing pathogens that are commonly causative in infections of the respiratory tract or skin and skin structure. Depending on the infection being treated, cefdinir can be administered as a convenient once-or twice-daily 5-or 10-day regimen. Clinical evidence indicates that cefdinir is an effective and generally well tolerated drug with superior taste over comparator antibacterial agents and is therefore a good option for the treatment of adults, adolescents and paediatric patients with specific mild-to-moderate respiratory tract or skin infections, particularly in areas where β-lactamase-mediated resistance among common community-acquired pathogens is a concern. Cefdinir has a broad spectrum of antibacterial activity encompassing a number of Gram-positive and -negative pathogens that are commonly causative in community-acquired respiratory and skin infections. Results of many studies published since 1995 show that cefdinir has good activity against penicillin-susceptible strains of Streptococcus pneumoniae, S. pyogenes and methicillin-susceptible Staphylococcus aureus, including β-lactamase-producers. However, in common with many other β-lactam antibacterials, cefdinir shows less activity against penicillin-intermediate and -resistant pneumococci and is inactive against methicillin-resistant S. aureus. Cefdinir is also active against the important respiratory tract Gram-negative pathogens Haemophilus influenzae and Moraxella catarrhalis, including β-lactamase-producing strains of both micro-organisms. In addition, the drug shows good in vitro activity against H. parainfluenzae. Cefdinir is stable to hydrolysis by many plasmid-encoded β-lactamases, including TEM-1, TEM-2, TEM-6, TEM-7, TEM-9, TEM-10, HMS-1, CAZ-2, SHV-1, OXA-1, OXA-2, OXA-3 and P99 type 1a. However, it is susceptible to hydrolysis by TEM-3, TEM-4, TEM-5, PSE-2, P99 type 1c, SHV2, SHV-3, SHV-4, SHV-5, MEN-1, K-l, CARB-1, CARB-2, CARB-3 and OXA-4 β-lactamases. The bactericidal effect of cefdinir is achieved by its binding to penicillinbinding proteins. This leads to damage of the cell wall, cell lysis and death of susceptible bacteria. Cefdinir is rapidly bactericidal against a number of pathogens at minimum bactericidal concentrations of two to four times the minimum inhibitory concentration. Cefdinir has also shown efficacy in several animal models of infection, including pneumonia caused by H. influenzae or penicillinsusceptible strains of S. pneumoniae and subcutaneous abscesses induced by S. aureus. In adults, mean maximum plasma cefdinir concentrations (Cmax) were 1.6 and 2.87 mg/L after single doses of 300mg and 600mg at a mean time of ≈3 hours. In paediatric patients, mean cefdinir Cmax values were 2.3 and 3.86 mg/L approximately 2 hours after administration of 7 and 14 mg/kg doses of the suspension. Cefdinir has a linear pharmacokinetic profile over the 200–400mg dose range, but displays nonlinear pharmacokinetics at a higher dose (600mg). At therapeutic dosages, cefdinir does not accumulate in the plasma of individuals with normal renal function. Cefdinir has an estimated bioavailability of 21% and 16% after administration of single 300 and 600mg capsules, and an estimated absolute bioavailability of 25% after administration of the suspension. The rate and extent of absorption of cefdinir decrease, although not clinically significantly, when the drug is taken with a high-fat meal. Thus, cefdinir may be taken without regard to food. The mean volume of distribution of cefdnir is 1.56–2.09 L/kg in adults and 0.67 L/kg in paediatric patients. The drug is 60–73% plasma protein bound. Cefdinir is widely distributed and achieves clinically relevant concentrations in bronchial mucosa, epithelial lining fluid, tonsillar tissue, sinus tissue, skin blister fluid and middle ear fluid. Cefdinir is not metabolised to an appreciable extent and is eliminated via the kidneys. After single oral doses of 300 or 600mg, renal clearance was ≈2 mL/min/ kg and apparent oral clearance values were 11.6 and 15.5 mL/min/kg. The plasma elimination half-life of cefdinir is 1.5–1.7 hours in adults and 1.2–1.5 hours in healthy infants and children. The pharmacokinetics of cefdinir are altered in patients with renal impairment and dosage modification is required for those with a creatinine clearance (CLcr) of 80% for cefdinir and the comparator groups). In a single trial in adults and adolescents with community-acquired pneumonia (CAP), cefdinir 300mg twice daily for 10 days was equivalent to cefaclor 500mg three times daily for 10 days in terms of both clinical and bacteriological efficacy at the TOC assessments. Clinical success rates with cefdinir and cefaclor were 89% and 86%, respectively, and bacteriological eradication rates were >90% for both groups. Cefdinir 300mg twice daily or 600mg once daily for 10 days showed clinical and bacteriological efficacy equivalent to that of standard regimens of amoxicillin/ clavulanic acid in trials conducted in adults and adolescents with acute bacterial rhinosinusitis. Clinical responses (clinical cure, or cure plus improvement) were achieved in ≥87% of patients at the TOC visits. Adults and adolescents with streptococcal pharyngitis/tonsillitis were also successfully treated with cefdinir 300mg twice daily (for 5 or 10 days) or 600mg once daily for 10 days. Cefdinir was at least as effective as penicillin V (250mg four times daily for 10 days). High rates of eradication of S. pyogenes were reported with cefdinir (88.5–91.7%) and both eradication rates and clinical cure rates with 10-day courses of cefdinir were significantly (p ≤0.02) higher than rates achieved with penicillin V at the TOC assessment. Cefdinir 300mg twice daily for 10 days was also an effective treatment for adults and adolescents with skin and skin structure infections and showed clinical and bacteriological efficacy similar to that of cefalexin. Paediatric Patients: In the treatment of paediatric patients with acute otitis media, cefdinir, administered as a suspension, at a dosage of 7 mg/kg twice daily for 5 or 10 days or 14 mg/kg once daily for 10 days, showed similar clinical efficacy to that of standard regimens of amoxicillin/clavulanic acid or cefprozil. Cefdinir was also an effective treatment for paediatric patients with streptococcal pharyngitis/tonsillitis. In two comparative trials, rates of eradication of S. pyogenes in patients treated with cefdinir 14 mg/kg/day for 5 or 10 days were significantly (p < 0.001) higher (>90%) than in recipients of 10-day courses of penicillin V 40 mg/kg/day (≈70%). In addition, clinical cure rates with 10-day courses of cefdinir (≥96%) were significantly (p = 0.001) higher than the clinical cure rate (86.3%) in the penicillin V treatment group. Cefdinir 7 mg/kg twice daily for 10 days showed good clinical and bacteriological efficacy, equivalent to that of cefalexin, in paediatric patients with uncomplicated skin and skin structure infections. Cefdinir was generally well tolerated by adults, adolescents and paediatric patients in randomised clinical trials that enrolled patients with respiratory tract or skin infections. Most reported adverse events were minor and self-limiting and discontinuation rates due to adverse events were low (1–6%). As with most antibacterials, pseudomembranous colitis has occasionally been reported in recipients of cefdinir. Overgrowth of Clostridium difficile should therefore be considered in patients presenting with diarrhoea during treatment. Adults and Adolescents: According to pooled data from US clinical trials, diarrhoea (incidence 15%) was the most common adverse event in adults and adolescents receiving cefdinir capsules at therapeutic dosages. Similarly, in individual randomised trials, diarrhoea (usually mild) was the most common event (incidence 7.8–33%) in patients treated with cefdinir 300mg twice daily or 600mg once daily. Nausea and headache were the other most frequently reported events (incidence ≤3%) in the pooled analysis. The incidence of most adverse events (e.g. nausea and headache) with cefdinir is similar to that reported for cefaclor, cefprozil, cefuroxime axetil, loracarbef, penicillin V and amoxicillin/clavulanic acid. However, in comparative trials, the incidence of diarrhoea was significantly (all p ≤0.04) higher in recipients of cefdinir than in those treated with cefaclor, cefprozil, cefalexin, loracarbef or penicillin V. The overall incidence of adverse events in cefdinir treatment groups was also significantly (p ≤0.008) higher than in recipients of cefaclor, loracarbef or cefalexin. However, discontinuation rates due to adverse events were similar for cefdinir and the comparator groups in all but two trials in which discontinuation rates were significantly lower (p ≤0.02) with cefdinir than with amoxicillin/ clavulanic acid. Paediatric Patients: In a pooled analysis of US clinical trials, and in individual randomised trials, diarrhoea (incidence 8% in the pooled analysis, 2.9–15.9% in the individual trials) was the most common adverse event in paediatric patients receiving cefdinir suspension at therapeutic dosages. Other adverse events included rash and vomiting (incidence ≤3%). In comparative trials, the incidence of adverse events with cefdinir suspension was similar to that reported for cefprozil, penicillin V or cefalexin suspensions. In addition, the incidence of diarrhoea with cefdinir was broadly similar to that reported for cefprozil, penicillin V suspension or amoxicillin/clavulanic acid suspensions. The overall incidence of adverse events with amoxicillin/clavulanic acid was significantly higher than in recipients of cefdinir 14 mg/kg once daily (26.2% vs 16.7%; p = 0.01) in one comparative trial in patients with acute otitis media. In a similar trial, diarrhoea occurred significantly (p < 0.001) more frequently with amoxicillin/clavulanic acid (35%) than with cefdinir 7 mg/kg twice daily (13%) or 14 mg/kg once daily (10%). Rates of treatment discontinuation due to adverse events were similar in recipients of cefdinir, cefprozil or penicillin V. Discontinuation rates in cefdinir recipients were similar to or lower than rates reported for patients treated with amoxicillin/ clavulanic acid. Cefdinir is approved in the US for the treatment of adults, adolescents and paediatric patients with mild-to-moderate bacterial infections caused by susceptible strains of specific pathogens. The drug is available as capsule and strawberryflavoured suspension formulations and can be administered without regard to food. When given concomitantly, antacids containing magnesium/aluminium, and iron supplements, reduce the the absorption of cefdinir. These agents should be taken ≥2 hours before or after administration of cefdinir. In adults and adolescents, cefdinir is approved for the treatment of CAP, ABECB, acute maxillary rhinosinusitis, pharyngitis/tonsillitis, and uncomplicated skin and skin structure infections. Approved dosages are 300mg every 12 hours for 10 days (for CAP, uncomplicated skin and skin structure infections, and acute maxillary rhinosinusitis), 300mg every 12 hours for 5 or 10 days (ABECB and pharyngitis/tonsillitis) and 600mg every 24 hours for 10 days (ABECB, acute maxillary rhinosinusitis and pharyngitis/tonsillitis). Dosage modification is required for patients with renal impairment (CLcr 2), the recommended dosage of cefdinir is 7 mg/kg (to a maximum of 300mg) once daily.

This publication has 116 references indexed in Scilit: