Multiple dose pharmacokinetics of cefpodoxime in young adult and elderly patients

Pharmacokinetics and Target Attainment of ß-lactam Antibiotics in Older People: A Systematic Review of Current Literature

BACKGROUND AND OBJECTIVE

(Patho)physiological changes in older people may influence the pharmacokinetics (PK), and consequently the target attainment, of ß-lactam antibiotics using standard dosing regimens. This systematic review compiles the current knowledge on the PK and target attainment of ß-lactam antibiotics in older people, with the aim to identify priorities for dose optimization in this patient population.

METHODS

A systematic literature search of the PubMed and EMBASE databases was conducted. Relevant articles published prior to 1 December 2021 were identified as eligible when they included data on the PK of ß-lactam antibiotics in adults ≥ 65 years of age. Extracted information included reported PK parameters (volume of distribution, clearance [CL], elimination rate constant, intercompartmental CL, elimination half-life, area under the concentration-time curve, maximum and trough concentration), covariates on PK parameters, target attainment rate, and dosing recommendations.

RESULTS

Ninety-one relevant articles were included in this review. Four main ß-lactam subclasses were represented: 59.3% on cephalosporins + cephamycins, 25.3% on penicillins, 15.4% on carbapenems, and 3.3% on monobactams; 65.9% of articles involved intravenous administration, 16.5% mixed administration routes, 12.1% oral administration, and 5.5% intramuscular administration. The majority of studies had a small sample size, often did not include detailed information on the study population and methods, and were fairly old. CL was, on average, decreased, while elimination half-life was prolonged in aged subjects compared with young subjects. Volume of distribution was generally similar between age groups. Most studies identified renal function as the most important contributor to altered drug CL. In only 30.8% of the articles, target attainment was studied, and in 35.7% of these articles, target attainment was found to be suboptimal. Dosing recommendations were incorporated in 87.9% of articles.

CONCLUSION

Studies frequently fail to provide an evidence-based dosing recommendation for this diverse patient population. Model-based PK studies that address both physiological and disease-related changes are urgently needed. This review identified gaps of knowledge to set priorities for further research.

Cefpodoxime proxetil

A comprehensive profile of cefpodoxime proxetil including the nomenclatures, formulae, elemental composition, appearance, uses, and applications. The methods which were developed for the preparation of the drug substance and their respective schemes are outlined. The physical characteristics of the drug including the ionization constant, solubility, X-ray powder diffraction pattern, differential scanning calorimetry, thermal behavior, and spectroscopic studies are included. The methods which were used for the analysis of the drug substance in bulk drug and/or in pharmaceutical formulations includes the compendial, spectrophotometric, electrochemical and the chromatographic methods. The other studies which was carried out on this drug substance are including the drug stability, pharmacokinetics, bioavailability, drug evaluation, comparison and several compiled reviews. Finally, more than two hundred references are listed at the end of this profile.

Disposition of orally administered cefpodoxime proxetil in foals and adult horses and minimum inhibitory concentration of the drug against common bacterial pathogens of horses

OBJECTIVES

To determine the disposition of orally administered cefpodoxime proxetil in foals and adult horses and measure the minimum inhibitory concentrations (MICs) of the drug against common bacterial pathogens of horses.

ANIMALS

6 healthy adult horses and 6 healthy foals at 7 to 14 days of age and again at 3 to 4 months of age.

PROCEDURE

A single dose of cefpodoxime proxetil oral suspension was administered (10 mg/kg) to each horse by use of a nasogastric tube. In 7- to 14-day-old foals, 5 additional doses were administered intragastrically at 12-hour intervals. The MIC of cefpodoxime for each of 173 bacterial isolates was determined by use of a commercially available test.

RESULTS

In 7- to 14-day-old foals, mean +/- SD time to peak serum concentration (Tmax) was 1.7 +/- 0.7 hours, maximum serum concentration (Cmax) was 0.81 +/- 0.22 microg/mL, and elimination half-life (harmonic mean) was 7.2 hours. Disposition of cefpodoxime in 3- to 4-month-old foals was not significantly different from that of neonates. Adult horses had significantly higher Cmax and significantly lower Tmax, compared with values for foals. The MIC of cefpodoxime required to inhibit growth of 90% of isolates for Salmonella enterica, Escherichia coli, Pasteurella spp, Klebsiella spp, and beta-hemolytic streptococci was 0.38, 1.00, 0.16, 0.19, and 0.09 microg/mL, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

Oral administration at a dosage of 10 mg/kg every 6 to 12 hours would appear appropriate for the treatment of equine neonates with bacterial infections.

Pharmacokinetics of cefpodoxime proxetil in healthy young and elderly volunteers

The influence of age on the pharmacokinetics of cefpodoxime was evaluated in 12 elderly (ages 65-85 years) and 12 weight- and sex-matched young (ages 20-33 years) subjects, each of whom received two cefpodoxime proxetil 200-mg tablets every 12 hours for 14.5 days. Serial blood samples and urine were collected after the first dose on day 1, after the morning dose on day 8, and after the last (morning) dose on day 15. Plasma and urine samples were assayed for cefpodoxime concentrations using HPLC methods. Within each age group, mean pharmacokinetic parameters determined on day 1 were similar to corresponding values on days 8 and 15, indicating that cefpodoxime does not accumulate after twice-daily dosing of cefpodoxime proxetil. Based on this result, parameters were pooled across days in each age group. No significant differences were observed between healthy and elderly volunteers in area under the plasma concentration-time curve for the 12-hour dosing interval, peak plasma concentration, or time to peak concentration. Mean urinary excretion and renal clearance of cefpodoxime were significantly lower in elderly subjects. Differences in renal clearance were attributed to the corresponding age-related reduction that was noted in creatinine clearance values, whereas the lower urinary excretion of cefpodoxime probably reflected slightly reduced systemic drug absorption in the elderly. Differences in these parameters between groups were less than 30%, and were unlikely to be of clinical importance. The data indicate that dose adjustment of cefpodoxime in elderly subjects having normal (age-adjusted) creatinine clearance values is not required.

Cefpodoxime proxetil: a new, broad-spectrum, oral cephalosporin

OBJECTIVE

To discuss the chemistry, pharmacokinetics, spectrum of activity, clinical trials, adverse effects, drug interactions, and dosage guidelines of cefpodoxime proxetil.

DATA SOURCES

Literature was identified through a MEDLINE search from 1988 to the present and from review of bibliographies in that literature.

STUDY SELECTION

Data were limited to comparative trials published in the English literature. Although many studies were conducted in Japan, the results often were available only in Japanese or partly in English. As these studies could not be completely evaluated, they are not included in this review.

DATA SYNTHESIS

Cefpodoxime exhibits good activity against many gram-positive and gram-negative organisms. In clinical trials, cefpodoxime was similar in both clinical and bacteriologic efficacy to amoxicillin, cefaclor, amoxicillin/clavulanate, and penicillin in the treatment of respiratory and urinary tract infections. It also appeared effective in the treatment of skin and soft tissue infections, although no comparative trials have been performed. Cefpodoxime is well tolerated by children and is effective in the treatment of otitis media and pharyngitis. It has a similar adverse effect profile to that of other penicillins and cephalosporins, with gastrointestinal effects being most common.

CONCLUSIONS

Cefpodoxime demonstrates good in vitro activity against pathogens frequently associated with respiratory tract, urinary tract, and skin and tissue infections. It has not demonstrated greater efficacy than the other antibiotics to which it has been compared. The available published clinical trials are fraught with methodologic, statistical, and evaluative flaws. Thus, further trials comparing cefpodoxime with established treatments, as well as the newer cephalosporins, are needed before its place in therapy can be established.

Future directions in antimicrobial chemotherapy

New developments in the treatment of bacterial infections are discussed. The most important developments include oral broad-spectrum cephalosporin derivatives and extended-spectrum injectable cephalosporins with improved activity against Gram-positive bacteria. Meropenem is a new carbapenem agent with markedly improved activity against Gram-negative bacteria. Many fluoroquinolones are in various phases of development. The most interesting new compound is sparfloxacin. Azithromycin is a new macrolide which, because of its very long half-life, attains very high levels in most tissues. Potential uses of the newer agents are discussed.

Disposition of cefpodoxime proxetil in healthy volunteers and patients with impaired renal function

The disposition of cefpodoxime in 24 subjects with various degrees of renal function after administration of a single oral dose of 200 mg of cefpodoxime proxetil (equivalent to 200 mg of cefpodoxime activity) was studied. Subjects were assigned to one of four groups (six per group): group I, normal renal function (creatinine clearance [CLCR], greater than ml/min); group II, mild renal impairment (CLCR, 50 to 80 ml/min); group III, moderate renal impairment (CLCR, 30 to 49 ml/min); or group IV, severe renal impairment (CLCR, 5 to 29 ml/min). Although cefpodoxime terminal elimination half-life in group I (2.55 +/- 0.25 h [mean +/- standard deviation]) was not significantly different from that in group II (3.53 +/- 0.74 h), the half-life values for group III (5.90 +/- 1.67 h) and group IV (9.80 +/- 1.21 h) were significantly prolonged compared with those of group I. The mean absorption rate constant was similar among groups and ranged from 0.68 to 0.85 h-1. All groups exhibited absorption lag-times which were comparable (0.30 to 0.41 h), and the apparent volume of distribution was similar among groups. Cefpodoxime apparent total body clearance (CLP/F) values in groups II, III, and IV (132 +/- 29, 112 +/- 41, and 55.7 +/- 9.9 ml/min, respectively) were significantly lower than that in group I (238 +/- 44 ml/min). Cefpodoxime CLP/F was positively correlated with CLCR (r2 = 0.79; P less than 0.05): CLP/F = (1.9 CLCR) + 18.4. Renal clearance also declined with decreasing renal function. Adjustments in cefpodoxime organism and on the site and severity of infection. Simulated plasma concentration-time data from this study suggest that 200 mg of cefpodoxime proxetil administered every 12 to 24 h to subjects with CLcr between 30 and 49 ml/min and 200-mg dose taken every 24 h by subjects with CLcr between 5 and 29 ml/min will maintain cefpodoxime concentration in plasma similar to those in subjects with normal renal function who receive a standard dosage mg every 12 h.