Relationship between renal function and disposition of oral cefixime

Clinical pharmacokinetic of cefixime: a systematic review

Cefixime is an antibiotic from the cephalosporin class used to treat various bacterial infections. The purpose of performing this review is to thoroughly evaluate the pharmacokinetic (PK) data on cefixime.Five databases were systematically searched to identify studies on the PK of cefixime.A total of 38 articles meeting the eligibility criteria were included that provide data on concentration-time profiles or PK parameters such as peak plasma and serum concentration (C_max), area under the curve (AUC), clearance (CL), and time to reach C_max (t_max). A dose-dependent increase in AUC and Cmax of cefixime was depicted in healthy volunteers. The clearance of cefixime decreased according to the degree of renal insufficiency among haemodialysis patients. A significant difference in CL was found in comparing fasted and fed states. A biphasic decline in serum concentrations of cefixime was reported when it was taken without probenecid.This review compiles all the reports on the PK of cefixime in healthy and renally impaired patients; the summarized information can be used to optimize cefixime dosing in different disease states. Moreover, cefixime has increased time above MIC value suggesting that it may be an effective treatment for infections caused by certain pathogens.

Pattern, frequency and factors associated with inappropriate high dosing in chronic kidney disease patients at a tertiary care hospital in Pakistan

BACKGROUND

Patients with chronic kidney diseases (CKD) are susceptible to the toxic drug effects if given unadjusted doses. Although Pakistan harbors a high burden of CKD patients, there is limited information available on the frequency, pattern and factors associated with unadjusted drug doses among CKD patients.

METHODS

This cross-sectional study conducted at Sandeman Provincial Hospital, Quetta included 303 non-dialysis ambulatory CKD patients (glomerular filtration rate < 60 ml/min/1.73m²). The patients' data were collected through a purpose designed data collection form. The appropriateness of doses was checked against the renal drug handbook-2018, Kidney Disease Improving Global Outcomes guidelines, British National Formulary-2022, and manufacturer leaflets. Data were analysed by SPSS 23 and multiple binary logistic regression analysis was used to assess the factors associated with receiving inappropriate high doses. A p-value < 0.05 was considered statistically significant.

RESULTS

The patients received a total of 2265 prescription lines, with a median of eight different drugs per patient (interquartile range: 6-9 drugs). A total of 34.5% (783/2265) drugs required dose adjustment. Of these, doses were not adjusted for 56.1% (440) drugs in 162 (53.4%) patients. The most common pharmacological class of drugs requiring dose adjustment were antibiotics (79.1%), followed by antidiabetics (59.2%), diuretics (57.0%), angiotensin converting enzyme inhibitors (56.9%), beta blockers (56.9%), analgesics (56.0%), angiotensin receptor blockers (55.2%), domperidone (53.9%) and antihyperlipidmics (46.1%). Patient's age of 41-60 (OR = 5.76) and > 60 years (OR = 9.49), hypertension (OR = 2.68), diabetes mellitus (OR = 3.47) and cardiovascular diseases (OR = 2.82) had statistically significant association (p-value < 0.05) with inappropriate high doses.

CONCLUSION

The high frequency of inappropriate high doses suggests an important quality gap in medication dosing for patients with ND-CKD at the study site. Special attention should be paid to the drugs and patients with identified risk factors for receiving inappropriate high doses.

Evaluation of a novel method to estimate absolute bioavailability of drugs from oral data

The goal of this investigation was to evaluate the performance of a novel method allowing estimation of absolute bioavailability from oral data only. In contrast to the traditional method, which compares areas under the drug concentration time curves after oral and intravenous administration in subjects with normal renal function, the novel method uses total and renal clearance values following oral administration from subjects with varying renal functions to estimate bioavailability. The novel method can also provide estimates for nonrenal clearance.Published data on total clearance and renal clearance of drugs obtained from subjects with variable renal functions were collected, the novel method applied, estimates of bioavailability and nonrenal clearance obtained and compared with reported estimates by the traditional methods. In addition computations were performed to assess various factors that could possibly affect the reliability of the novel method. The results indicated that the novel method provides accurate estimates for bioavailability of drugs meeting the prerequisites: linear kinetics, predominant renal excretion in normals, absence of metabolic polymorphism and independence of bioavailability and nonrenal clearance from renal function. The average (standard deviation) of the prediction error and bias of the bioavailability estimates by the novel method was 7.8 (6.0) and -1.4 (9.8)%, respectively. The estimates for nonrenal clearance by the novel method were less accurate. The computations confirmed that the estimates by the novel method are sensitive to renal-function dependent changes in nonrenal clearance and bioavailability and also depend on the extent of renal excretion of a drug. In conclusion, the novel method's main use is to diagnose absence or presence of changes in bioavailability and non-renal clearance of drugs in populations with varying renal function.

Pharmacokinetics of cefixime in children with urinary tract infections after a single oral dose

The pharmacokinetics of cefixime, a third-generation broad-spectrum cephalosporin, were determined following administration of a 8 mg/kg single oral dose of cefixime suspension to six children with urinary tract infections, ages from 6 to 13 years and weights from 17 to 60 kg. Blood samples for determination of plasma cefixime concentrations were obtained for up to 12 hr and complete urine collections were obtained for urinary excretion of unchanged parent drug for up to 24 hr after administration. Plasma and urine concentrations of cefixime were determined using a reversed phase HPLC assay and pertinent pharmacokinetic parameters were estimated by model-independent standard methods. Mean peak plasma concentration was 4.04 micrograms/ml and was reached after 3.2 hr. The mean area under the plasma concentration-time curve was 33.07 micrograms.hr/ml and the mean elimination half-life was 3.91 hr. The mean apparent total clearance was 4.74 ml/min./kg and about 15% of the dose administered was recovered unchanged in urine. In conclusion, the estimated pharmacokinetic values of cefixime were comparable to those observed in healthy adult subjects based on equivalent mg/ kg doses. Plasma and urine concentrations of the drug were well above the reported minimal plasma and urinary concentrations for most common urinary tract pathogens for up to 12 and 24 hr after administration, respectively.

Cefixime. A review of its therapeutic efficacy in lower respiratory tract infections

Cefixime is an orally active third generation cephalosporin with in vitro antibacterial activity against most important lower respiratory pathogens. The drug is active against Haemophilus influenzae, Moraxella catarrhalis and penicillin-susceptible Streptococcus pneumoniae but not Staphylococcus aureus. Cefixime has a long elimination half-life (3 hours compared with 0.5 hours for cefaclor and 1.5 hours for cefalexin), which allows once daily administration. Several trials have established the clinical efficacy of the drug in patients with lower respiratory tract infection (LRTI). In comparative studies cefixime had similar efficacy to amoxicillin +/- clavulanic acid, cefaclor, cefalexin, cefuroxime axetil and clarithromycin. Trials evaluating the efficacy of cefixime as the oral component of intravenous to oral switch therapy have produced promising preliminary results although further carefully designed trials are needed in this area. As with certain other drugs of its class, gastrointestinal disturbances are the most frequently reported adverse events in patients taking cefixime and cases of pseudomembranous colitis have been reported. Thus, cefixime is an effective treatment for mild to moderate LRTI and may have a role as the oral component of intravenous to oral switch therapy although further well designed studies are needed to confirm initial favourable results in this important emerging area of antibacterial therapy.

Cefixime penetration in human renal parenchyma

The diffusion of cefixime, a new orally active expanded-spectrum cephalosporin, was studied in 12 patients undergoing nephrectomy after receiving 200-mg oral doses every 12 h for 2 days. The patients were divided into two groups according to the time of perioperative sampling after the last dose: 4 h (group 1) and 12 h (group 2). Preoperative blood samples were taken just before administration of the last dose of cefixime. Simultaneous blood and tissue samples were collected perioperatively at 4 h (time to peak level) and 12 h (residual level). The intrarenal concentrations of cefixime were measured by an isocratic reversed-phase high-pressure liquid chromatographic (HPLC) assay. Concentrations in serum were determined by both microbiological and HPLC assays. The mean peak levels in serum were 3.41 +/- 0.43 micrograms/ml (group 1), and the residual levels averaged 1.54 +/- 1.17 micrograms/ml (group 2). The diffusion in renal parenchyma was not significantly different in the cortexes and medullas of both groups of patients: 5.7 to 6.4 micrograms/g in group 1 and 4.6 to 4.7 micrograms/g in group 2. The decrease in cefixime concentrations was slower in tissue than in serum; the ratios of concentrations in tissue to those in serum were 3.5 to 3.6 and 1.7 to 1.9 at 4 and 12 h, respectively. The intrarenal concentrations of cefixime remained higher than the MIC for the most susceptible gram-negative bacteria during the time interval between the administration of two doses.