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Comparative evaluation of cefadroxil and cephalexin in children and adolescents with pyodermas. Cefadroxil Once Daily Pyoderma Study Group.

This randomized, multicenter study compared the safety and efficacy of cefadroxil with that of cephalexin for the treatment of pyodermas in children and adolescents (1-18 years of age). Cefadroxil was given as a single oral daily dose of 30 mg/kg, and cephalexin 30 mg/kg/day was given in two divided doses. The maximum daily dose for both drugs was 1 gm, and treatment was administered for 10 days. Clinical and bacteriologic evaluations were made on days 4 or 5 during therapy and 2 to 4 days after therapy was completed. Of the 462 patients enrolled in the study, 156 patients in the cefadroxil group and 133 patients in the cephalexin group were evaluable. Staphylococcus aureus (56% of isolates) and Streptococcus pyogenes (39% of isolates) were isolated most frequently. The bacteriologic response was statistically greater in the patients treated with cefadroxil than in those treated with cephalexin (96% versus 89%; P = 0.042). A satisfactory clinical response was reported in 147 (94%) cefadroxil-treated patients and 122 (92%) cephalexin-treated patients (P = 0.476). The overall effective response to treatment was significantly higher with cefadroxil than with cephalexin (94% versus 86%; P = 0.024). Compliance with 9 or 10 days of therapy was similar in both treatment groups, although there was a difference between the two treatment groups with respect to completion of medication regimen: 95% of patients taking cefadroxil once daily--versus 65% of patients taking cephalexin twice daily--took 100% of their medication (P < 0.0001). Adverse events were infrequent and mild. The results of this study demonstrate that once-daily cefadroxil offers greater bacteriologic eradication and a better overall effective response than twice-daily cephalexin for the treatment of pyodermas caused by gram-positive pathogens in children and adolescents.

Adolescent↗

Concentrations of ampicillin and cefadroxil in human serum and mixed saliva following a single oral administration of talampicillin and cefadroxil, and relationships between serum and mixed saliva concentrations.

The concentrations of ampicillin (ABPC) from talampicillin (TAPC) and cefadroxil (CDX) in serum and mixed saliva were assayed by the thin layer disc plate method. Talampicillin and cefadroxil (500 mg) were given by a single oral administration. The relationships between serum and mixed saliva ampicillin and cefadroxil concentrations were evaluated in the paired specimens collected from 10 different persons, respectively. The means of concentration ratios of mixed saliva to serum ampicillin and cefadroxil were 0.006 +/- 0.003 and 0.025 +/- 0.010 (mean +/- SD), respectively. Significant correlation coefficients between mixed saliva and serum concentrations were found for both ampicillin and cefadroxil, which were r = 0.78, P less than 0.001, and r = 0.67, P less than 0.001, respectively.

Adult↗

PEPT2 (Slc15a2)-mediated unidirectional transport of cefadroxil from cerebrospinal fluid into choroid plexus.

Cefadroxil is a cephalosporin antibiotic used in the treatment of infection. However, cerebrospinal fluid (CSF) concentrations of cefadroxil and other aminocephalosporins are not adequate for the treatment of bacterial meningitis. To evaluate the relevance of PEPT2 in affecting the exposure of aminocephalosporins in brain, we investigated the transport properties of cefadroxil at the blood-CSF interface using primary-cultured epithelial cells and isolated whole tissues of choroid plexus. Our results indicated that cefadroxil was preferentially taken up from the apical as opposed to basal side of the monolayer (5-fold), and its apical uptake was stimulated by an inwardly directed proton gradient. The concentration-dependent apical uptake of cefadroxil was characterized by a high-affinity/low-capacity transport system (Km = 39.0 +/- 22.7 microM; Vmax = 22.9 +/- 6.6 pmol/mg/min) and a nonsaturable component (Kd = 0.15 +/- 0.01 microl/mg/min); in contrast, only a nonsaturable component was found for the basal uptake of cefadroxil (Kd = 0.14 +/- 0.01 microl/mg/min). The apical-to-basal transepithelial transport of 2 microM cefadroxil was greater than its basal-to-apical transport, but no differences were observed in directionality when 5 mM concentrations of cefadroxil were studied. Moreover, the cellular efflux of cefadroxil was not saturable in either direction (i.e., to apical or basal side). Finally, no differences were observed in the choroid plexus tissue efflux of 2 microM cefadroxil from wild-type and PEPT2 null mice. These findings demonstrate that PEPT2 has an important role in limiting the exposure of cefadroxil in CSF. Located at the apical membrane of choroid plexus epithelium, PEPT2 acts in a unidirectional (as opposed to bidirectional) manner in transporting cefadroxil from CSF into the cell.

Animals↗

[Therapeutic experience with cefadroxil syrup in acute infections, especially scarlet fever, in pediatric field (author's transl)].

Clinical effects were investigated on cefadroxil powder for syrup (containing 100 mg of cefadroxil per 1 g) for acute bacterial infections (mostly scarlet fever) in the field of pediatrics, and the results were obtained as follows. Cefadroxil was applied in 100 cases of scarlet fever. Among 49 cases administered 30-39 mg/kg/day, the results were excellent in 34 cases and good in 15 cases, efficacy ratio being thus 100%. Among 38 cases administered 40-49 mg/kg/day, the results were excellent in 33 cases, and good in 5 cases, efficacy ratio being thus 100%. Out of 4 cases administered 20-29 mg/kg/day, the results were excellent in 3 cases and good in 1 case, while out of 9 cases administered 50-59 mg/kg/day, excellent in 4 cases and good in 5 cases. Among 78 cases of scarlet fever from which beta-hemolytic Streptococcus was proven from swab liquid of palatal tonsil, 67 cases received cefadroxil at a daily dose of 30-49 mg/kg, and the bacteria turned to negative the next day of administration in 72 cases, 2 days later in 6 cases. Cefadroxil was administered at a daily dose of 46 mg/kg for 7 days in 1 case of SSS syndrome of which Staphylococcus aureus was proven from skin lesion, and local bacteria turned to negative, as well as clinical effect was excellent. No pathogen was proven in 1 case of acute tonsillitis, maybe because ampicillin (ABPC) and cefazolin (CEZ) were administered before cefadroxil treatment, and yet a clinical efficacy was judged by administering cefadroxil at a daily dose of 46 mg/kg, though no clinical improvement was observed with the prior antibiotics. As to the side effects of cefadroxil in 102 cases, a slight vomiting was noticed in 6 cases, though the administration could be continued, and a slight rise of GOT or GPT was observed respectively in 3 cases and 1 case, all of which were recovered without abnormal clinical findings. Among the patients of scarlet fever, after beta-hemolytic Streptococcus became negative, reelimination or recurrence was noticed in 2 cases, but these patients were cured completely by readministration of cefadroxil or administration of amoxicillin (AMPC). Cefadroxil powder for syrup was absorbed quite well, its serum levels were maintained for long, and it was easily administered in children. Considering from its superior antibacterial activity, cefadroxil may be expected to be useful for a remedy in slight or middle infections of children.

Cefadroxil↗

Dose-dependent absorption and elimination of cefadroxil in man.

The pharmacokinetic behaviour of cefadroxil was dose-dependent in healthy male volunteers following the oral administration of single doses of 5, 15, and 30 mg.kg-1. As the dose of cefadroxil increased from 5 to 15 and 30 mg.kg-1, the peak plasma concentrations, normalized to 5 mg.kg-1, decreased significantly from 15.1 to 10.7 and 7.6 mg.l-1, while the corresponding normalized areas under the plasma concentration-time curves from 0 to 2 h decreased significantly from 1258 to 946 and 801 min.mg.l-1. When the same subjects were given 5 mg.kg-1 of cefadroxil together with 45 mg.kg-1 of cephalexin, the absorption of cefadroxil was slowed to a similar or greater extent than with the high dose of cefadroxil. Although the absorption rate decreased as the dose increased, the systemic availability of cefadroxil was essentially complete at all doses, as judged by the 24 h urinary recoveries of the antibiotic. Kinetic analysis of the plasma concentration-time curves gave the best fit with a zero-order followed by a first-order absorption process, consistent with saturable intestinal absorption of cefadroxil. The elimination rate of cefadroxil was directly related to dose and plasma concentrations, and the clearance at the dose of 5 mg.kg-1 was significantly increased by the simultaneous administration of high-dose cephalexin. The renal clearance of cefadroxil ranged from 98 ml.min.l-1 at total plasma cephalosporin (cefadroxil + cephalexin) concentrations less than 2.5 mg.l-1 to 156 mg.l-1 at concentrations greater than 40 mg.l-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗

Uptake of cefadroxil derivatives in rat intestinal brush-border membrane vesicles.

Uptake of cefadroxil and its two acetyl-derivatives, N-acetyl- and O-acetyl-cefadroxil, into the brush-border membrane vesicles (BBMV) was measured at [pH]o = 5.5, 7.4 and [pH]i = 7.4. Both acetyl-derivatives showed a significantly slower uptake than cefadroxil at [pH]o = 5.5 and 7.4. Cefadroxil and the two derivatives showed a higher uptake rate in the presence of an inward H+ gradient ([pH]o = 5.5, [pH]i = 7.4). At [pH]o = 5.5, uptake of cefadroxil into BBMV was inhibited by N-acetyl-, O-acetyl-, N-BOC-, and N-BOC-O-acetyl-cefadroxil, but not by cephalothin and cefuroxime. At [pH]o = 7.4, no inhibition of cefadroxil uptake was evident for any inhibitors. There were two different transporters responsible for the uptake of cefadroxil at pH 5.5 and 7.4. One is the H(+)-coupled dipeptide transport system, and the other is the neutral pH-preferring system. The alpha-amino group may be essential for the transport of cefadroxil by both transport systems. Although the phenolic group in the side chain is not an essential functional group of beta-lactam antibiotics, an additional derivation on the phenolic group of cefadroxil also inhibited both the H(+)-coupled dipeptide transport system and the neutral pH-preferring transport system.

Animals↗

[The biological availability of cefadroxil given simultaneously with N-acetylcysteine].

A preliminary study revealed that similarly to the antibiotics amoxillin, thiamphenicol, erythromycin and doxycycline, the oral cephalosporin cefadroxil (CAS 66592-87-8) can be administered simultaneously with the mucolytic n-acetylcysteine (CAS 616-91-1). In the present study 12 healthy male volunteers received in a randomised cross-over design a single oral dose of 1000 mg cefadroxil or a single oral dose of 1000 mg cefadroxil (Bidocef) plus 200 mg n-acetylcysteine. The two study days were separated by a wash-out period of one week. To determine the pharmacokinetic profile of cefadroxil, plasma and sputum were analysed by HPLC at defined intervals. Regarding the bioavailability of cefadroxil, the free combination is bioequivalent to the individual component. After administration of cefadroxil plus n-acetylcysteine, a higher cefadroxil concentration was found in the sputum compared to an administration of cefadroxil alone. However, the difference was not statistically significant. According to the results, simultaneous administration of the oral cephalosporin cefadroxil and the mucolytic n-acetylcysteine is possible without changes in the bioavailability of cefadroxil being observed.

Acetylcysteine↗

[General pharmacology of cefadroxil (author's transl)].

The general pharmacological properties of cefadroxil which is a new semisynthetized cephalosporin were examined and following results were obtained. 1) Cefadroxil had no appreciable influences on the central nervous system in mice and the EEG in cats. 2) Cefadroxil had no effects on the isolated smooth muscle organs. 3) Cefadroxil had no effects on the passage of charcoal meal in mice and the motility of the stomach in situ in rabbits. 4) Cefadroxil inhibited the gastric secretion in pylorus-ligated rats. 5) Cefadroxil induced no marked changes in the respiration, blood pressure, heart rate, electrocardiogram and femoral blood flow in anesthetized dogs. Cefadroxil had no effects on the isolated hearts and ear vessles of rabbits. 6) Cefadroxil decreased the urine volume and the excretion of electrolytes (Na+, K+ and Cl-) in first three hours in rats. 7) Cefadroxil increased the biliary secretion in rats. No significant effects of cefadroxil were found in the other pharmacological experiments.

Animals↗

A pharmacokinetic comparison of cefadroxil and cephalexin after administration of 250, 500 and 1000 mg solution doses.

The pharmacokinetics of cefadroxil and cephalexin were examined following single oral doses of either 250, 500 or 1000 mg to a total of 36 healthy volunteers. The volunteers were divided into groups of 12 per dose-group and solution doses of cefadroxil or cephalexin were administered after an overnight fast according to a crossover design for the cephalosporins but not for doses. Serial blood and urine samples were collected from each individual and were analyzed for cefadroxil or cephalexin using validated HPLC assays with UV detection. The individual subject plasma concentration-time data for each cephalosporin were analyzed using noncompartmental methods. Profiles for cephalexin in plasma showed sharper and higher peaks than those for cefadroxil. Although values for the peak concentrations (Cmax) for cefadroxil were lower than that of cephalexin, the levels of cefadroxil in plasma and urine remained above the reported minimum inhibitory concentrations of susceptible organisms for longer period of time than those of cefalexin. The elimination half-life (t1/2) of cefadroxil (about 2 h) was significantly longer than that of cephalexin (about 1 h). The values for Cmax and AUC0-infinity values for both these cephalosporins showed dose-proportional increase, whereas t1/2, renal clearance (CLR) remained independent of dose. These observations confirm that cefadroxil and cephalexin obey linear pharmacokinetics. The CLr of both the cephalosporins were significantly higher than the average glomerular filtration rate at each dose level. The urinary recovery (% Xu) of each cephalosporin, accounted for over 80 per cent of the administered dose, and no significant differences in % Xu were observed between the two cephalosporins. These data suggest that the systemic availability of cefadroxil and cephalexin is similar at each dose level.

Adult↗

Mechanisms of cefadroxil uptake in the choroid plexus: studies in wild-type and PEPT2 knockout mice.

The choroid plexus uptake of [(3)H]cefadroxil was studied in peptide transporter 2 (PEPT2) wild-type and null mice as a function of temperature, transport inhibitors, pH, and saturability. At normal pH (7.4) and temperature (37 degrees C), the uptake of 1 microM cefadroxil was reduced by 83% in PEPT2(-/-) mice as compared with PEPT2(+/+) mice (p < 0.001). A further reduction was achieved in null animals by reducing the temperature to 4 degrees C, or by adding saturating concentrations of unlabeled cefadroxil or p-aminohippurate (p < 0.05). Glycylsarcosine coadministration could inhibit the uptake of cefadroxil in PEPT2(+/+) mice (p < 0.01) but not PEPT2(-/-) mice. Although a proton-stimulated uptake of cefadroxil was demonstrated in PEPT2(+/+) mice (pH 6.5 versus pH 7.4; p < 0.01), no pH dependence was observed in PEPT2(-/-) mice. Kinetic parameters for cefadroxil (without p-aminohippurate) in wild-type mice were: V(max) = 5.4 pmol/mg/min, K(m) = 34 microM, and K(d) = 0.0069 microl/mg/min; in the presence of p-aminohippurate, the parameters were: V(max) = 4.1 pmol/mg/min, K(m) = 27 microM, and K(d) = 0.0064 microl/mg/min. In null animals, the kinetic parameters of cefadroxil (without p-aminohippurate) were: V(max) = 2.7 pmol/mg/min, K(m) = 110 microM, and K(d) = 0.0084 microl/mg/min; in the presence of p-aminohippurate, only a K(d) = 0.010 microl/mg/min was observed. Based on kinetic and inhibitor analyses, it was determined that (under linear conditions), 80 to 85% of cefadroxil's uptake in choroid plexus is mediated by PEPT2, 10 to 15% by organic anion transporter(s), and 5% by nonspecific mechanisms. These findings demonstrate that PEPT2 is the primary transporter responsible for cefadroxil uptake in the choroid plexus. Moreover, the data suggest a role for PEPT2 in the clearance of peptidomimetics from cerebrospinal fluid.

Animals↗

Cefadroxil kinetics and dynamics in a pediatric patient with acute osteomyelitis.

Cefadroxil has been used for the treatment of acute osteomyelitis. However, its pharmacokinetics and pharmacodynamics have not been studied in these patients. We evaluated the kinetics and dynamics of cefadroxil in a pediatric patient with osteomyelitis caused by Staphylococcus aureus. After initial clinical improvement on intravenous nafcillin, the patient received oral cefadroxil, 60 mg/kg every 12 h. Blood samples were collected at 0, 1, 2, 4, 6, 8 and 12 h; bactericidal titers were determined at 2 and 12 h. Cefadroxil was measured by an HPLC method. The peak and trough serum concentration of cefadroxil was 35.4 and 0.5 micrograms/ml, respectively. The oral clearance and elimination half-life were 11.5 ml/min/kg and 2.4 h, respectively. The peak bactericidal titer was 1:4 and the trough titer was less than 1:2 for the infecting organism. The child's finger appeared worse with an increase in swelling and erythema after 2 days of cefadroxil therapy. Cefadroxil was discontinued and the patient was treated successfully with intravenous nafcillin. The apparent failure of cefadroxil therapy can be explained by lower than recommended peak (greater than or equal to 1:8) and trough (greater than or equal to 1:2) titers for therapeutic success. Thus, an alternative dosage regimen of cefadroxil should be considered in the future studies.

Cefadroxil↗

[Clinical results of cefadroxil in children and pharmacokinetics of the drug (author's transl)].

Cefadroxil was administered orally at a daily dose of 30-40 mg/kg to 8 cases of the infection of upper respiratory tract mainly due to beta-hemolytic Streptococcus, and efficacy was obtained in 7 cases, this rate being considered to be satisfactory, though the cases were too few to reach a conclusion. As to pathogens of bacterial infection of upper respiratory tract, beta-hemolytic Streptococcus and Staphylococcus aureus were encountered especially frequently, and in view of antibacterial activity against these 2 bacteria, our results could be approved. Further investigations should be performed carefully, however, to determine if cefadroxil may be a drug of first choice in the treatment of severe bacterial pneumonia and pyothorax. No side effects were observed throughout our treatment, though digestive tract disorders, especially diarrhea, are most frequent in literatures. As to pharmacokinetical characteristic of cefadroxil, almost the same results were obtained to other reports, though our data are insufficient as our experience was limited in only 1 case. Serum levels were determined after 35.7 mg/kg of cefadroxil were administered once orally, and a peak of about 38 mcg/ml appeared 2 hours later, and a high level of about 30 mcg/ml was maintained at 5 hours, though an oral dose was high. Efficacy for large area of bacterial infections may be expected from these serum levels. From urine collected simultaneously, about 74% of cefadroxil was recovered within more than 4 hours. This showed that cefadroxil was well absorbed from digestive tract, and a major part was excreted rapidly through kidney. From the results of our experiment, characteristics of cefadroxil may be summarized as follows. Cefadroxil is absorbed well after oral administration, antibacterial action is fully expected from serum level, a major part is excreted through kidney, and clearance is good. Cefadroxil will be recommended especially for bacterial infections of upper respiratory tract due to beta-hemolytic Streptococcus and Staphylococcus aureus.

Cefadroxil↗

Linezolid versus cefadroxil in the treatment of skin and skin structure infections in children.

BACKGROUND: Skin and skin structure infections are common reasons for visits to pediatricians, accounting for up to 18%. Staphylococcus aureus and Streptococcus pyogenes are the most frequently isolated Gram-positive pathogens in uncomplicated skin infections. Increasingly outpatient infections involve antibiotic-resistant Gram-positive pathogens including methicillin-resistant S. aureus. METHODS: This randomized, blinded, comparator-controlled, multinational trial compared the efficacy and safety of linezolid and cefadroxil for treatment of uncomplicated skin/skin structure infections in pediatric patients. Children ages 5 to 11 years were to receive linezolid suspension [10 mg/kg (up to 600 mg)] or cefadroxil suspension [15 mg/kg (up to 500 mg)] every 12 h. Patients ages 12 to 17 years were to receive linezolid tablets (600 mg) or cefadroxil capsules (500 mg) every 12 h. Therapy lasted 10 to 21 consecutive days with a follow-up visit 10 to 21 days posttherapy. RESULTS: Linezolid and cefadroxil were consistently effective treatments across all primary and secondary efficacy assessments. At follow-up cure rates were 88.7% (205 of 231) for linezolid-treated and 86.2% (193 of 224) for cefadroxil-treated intent-to-treat patients; cure rates were 91.0% (201 of 221) for linezolid-treated and 90.0% (189 of 210) for cefadroxil-treated clinically evaluable patients. S. aureus was eradicated in 89.6% (120 of 134) linezolid-treated and 88.8% (111 of 125) cefadroxil-treated microbiologically evaluable patients. Gastrointestinal complaints were the most common adverse events reported, without significant differences between treatment groups, and myelosuppression was not observed in this study. CONCLUSIONS: Linezolid is well-tolerated and as effective as cefadroxil in treating uncomplicated skin infections in pediatric patients. Linezolid effectively treated infections caused by S. aureus, methicillin-resistant S. aureus and S. pyogenes.

Acetamides↗

[Laboratory and clinical studies on cefadroxil in the field of pediatrics (author's transl)].

Laboratory and clinical investigations were performed on cefadroxil, and the results were obtained as follows. (1) Sensitivity distribution of cefadroxil. In S. aureus, two peaks were observed with inoculum size of 10(8)/ml: 1.56-3.13 microgram/ml and 12.5-25 microgram/ml, while with inoculum size of 10(8)/ml, the distribution was in the range of smaller than or equal to 0.1-25 microgram/ml, and the sensitivity peak was 0.78-1.56 microgram/ml. In S. pyogenes, with inoculum size of 10(8)/ml, sensitivity distribution was in the range of 0.05-1.56 microgram/ml, and the peak was 0.05 microgram/ml. On the other hand, with inoculum size of 10(6)/ml, distribution was 0.0006-1.56 microgram/ml, and the peak was 0.0006-0.012 microgram/ml, thus sensitivity of cefadroxil being 2 tubes higher. In E. coli, with inoculum size of 10(8)/ml, strains showed mostly high resistance as more than 100 microgram/ml, whereas with inoculum size of 10(6)/ml sensitivity was distributed between 3.13-50 microgram/ml, and the peak was 12.5-25 microgram/ml. (2) Absorption and excretion of cefadroxil: A dose of cefadroxil 5 mg/kg, 10 mg/kg or 20 mg/kg was administered to 9 cases of children aged from 4 years and 6 months to 11 years and 9 months, and serum levels of the drug were measured. As the results, in the group of 5 mg/kg dosing, the value was 0.94 microgram/ml at 30 minutes, 3.55 microgram/ml at 60 minutes, 7.65 microgram/ml at 2 hours, 2.55 microgram/ml at 4 hours, and 1.09 microgram/ml at 6 hours. In the group of 10 microgram/ml dosing, value of the drug was 4.18 microgram/ml at 30 minutes, 10.70 microgram/ml at 1 hour, 12.75 microgram/ml at 2 hours, 8.05 microgram/ml at 4 hours, and 2.33 microgram/ml at 6 hours. In the group of 20 mg/kg dosing, value was 9.93 microgram/ml at 30 minutes, 18.43 microgram/ml at 1 hour, 24.70 microgram/ml at 2 hours, 15.50 microgram/ml at 4 hours, and 6.45 microgram/ml at 6 hours. Dose response was observed thus distinctly among 3 groups. Recovery ratio of cefadroxil in urine was 76.14% within 6 hours. (3) Clinical trial with cefadroxil: Cefadroxil was applied clinically in 80 cases (76 patients). These included 22 cases of lacunar tonsillitis, 13 cases of pharyngitis, 24 cases of bronchitis, 6 cases of pneumonia, 8 cass of urinary tract infection, 5 cases of hemolytic streptococcal infection, 1 case of cellulitis, and 1 case of otitis media. Efficacy was obtained in 72 cases out of 80 cases ratio being thus 90%. Change of organisms was proven in 35 cases, among which disappearance and reduction of organism were observed in 32 cases (91.45). No adverse reaction was noticed throughout all cases. No abnormal value was recognized in laboratory findings.

Age Factors↗

Studies on the renal excretion mechanisms of cefadroxil.

The mechanisms of renal excretion of cefadroxil were investigated in conscious rats. The drug was intravenously infused at several infusion rates (0.27, 1.08, 5.40, 12.00, and 31.35 mg/hr), and the total and renal clearances were determined after the steady-state was reached. Renal clearance accounted for approximately 91% of total clearance. Renal clearance of cefadroxil increased from 2.51 +/- 0.39 to 3.57 +/- 0.43 ml/min as the steady-state cefadroxil plasma concentration increased from 1.7 +/- 0.3 to 24.4 +/- 3.8 micrograms/ml, and this has been attributed to a saturable renal tubular reabsorption of the antibiotic. The ratio of unbound cefadroxil renal clearance to glomerular filtration rate was larger than unity, which indicates that the antibiotic also undergoes active renal tubular secretion. When cefadroxil was administered together with cephalexin, an increase in the renal clearance of cefadroxil was observed, which has been attributed to a competitive inhibition of the tubular reabsorption of cefadroxil by cephalexin. A pharmacokinetic model for the renal excretion of cefadroxil was developed, and mathematical expressions showing the relationship between renal clearance and steady-state plasma concentration were deduced.

Animals↗

Comparative human oral clinical pharmacology of cefadroxil, cephalexin, and cephradine.

At equivalent oral doses, cefadroxil has a longer serum half-life, slower urinary excretion rate, greater area under the serum level versus time curve than cephalexin or cephradine, and peak serum concentrations that are 75 to 80% those of cephalexin. The calculated, apparent in vivo volume of distribution of cefadroxil is greater than that of cephalexin. These properties infer greater persistence of cefadroxil in serum and urine and more prolonged in vivo bacterial exposure to cefadroxil than to cephalexin or cephradine. Neither cefadroxil nor cephalexin demonstrates drug accumulation on repeated administration. The serum levels achieved by cefadroxil are unaffected by food. The pharmacokinetic properties of cefadroxil are supportive of the development of clinical efficacy data which could indicate that cefadroxil could be administered at 12-h intervals.

Adult↗

Cefadroxil versus penicillin in the treatment of streptococcal tonsillopharyngitis.

In a randomized multicentre study the efficacy of phenoxymethyl-penicillin and cefadroxil was tested in the treatment of acute tonsillopharyngitis caused by group A streptococci. These organisms were detected in 269 of the 300 children studied. Of the 239 patients in whom results could be evaluated, 121 received penicillin and 118 cefadroxil. After ten days of therapy the microbiological failure rate was 19% in the penicillin group and 6.8% in the cefadroxil group (p less than 0.01). Ten of 23 cases of microbiological failure in the penicillin group and two of eight in the cefadroxil group also had clinical symptoms of infection. All streptococcal isolates were sensitive to penicillin, cefadroxil and clindamycin with the exception of one strain with intermediate sensitivity to cefadroxil. Seven strains had intermediate sensitivity to erythromycin and one was resistant. No penicillin tolerance was observed. Patients in whom penicillin therapy failed more frequently had beta-lactamase producing staphylococci in the pharyngeal flora in comparison to successfully treated patients. The clinical and bacteriological results showed that cefadroxil was clearly superior to penicillin.

Adolescent↗

Experimental studies on the influence of surfactants on intestinal absorption of drugs. Cefadroxil as model drug and sodium taurocholate as natural model surfactant: studies in rat colon and in rat duodenum.

The influence of the natural bile acid surfactant sodium taurocholate (CAS 81-24-3) on colic and duodenal (i.e. the proximal third of the small intestine) absorption of cefadroxil (CAS 50370-12-2) was studied using the in situ rat gut technique, and compared with the effect of sodium lauryl sulfate (CAS 151-21-3), the most widely used synthetic anionic surfactant. Previously, the stability, compatibility, and micelle-solubilization characteristics of taurocholate were assessed in order to correct, when necessary, the absorption results. White the passive absorption rate constants (kf, h-1) determined in colon in the presence of increasing lauryl sulfate concentrations showed an asymptotic value about 7-fold higher than that of cefadroxil alone, only a 2-fold higher value was obtained in the presence of taurocholate at similar concentrations. Therefore the natural surfactant would increase the polarity of the colic absorbent membrane much less than lauryl sulfate does (about 3.5 times). The effects of taurocholate on the duodenal absorption of cefadroxil, which is the sum of a single passive process and a simultaneous carrier-mediated transport, can be summarized as follows: 1. When the working concentration of cefadroxil is far from carrier saturation (0.1 mg/ml) a slight but clear net decrease in the apparent kf value is observed in the presence of increasing concentrations of the natural surfactant (from 3.0 to 2.3 h-1) 2. When the concentration of the antibiotic in the working fluid is above carrier saturation (10 mg/ml) the picture is reversed, and a slight net increase in kf in the presence of increasing concentrations of taurocholate (from 0.8 to 1.2 h-1) is found. This means that the effect of taurocholate as a noncompetitive inhibitor of active cefadroxil transport is very much smaller than that observed with lauryl sulfate. Moreover, the increase in passive absorption relative to the synthetic surfactant is also much smaller. On the basis of allometric considerations it could be concluded that for practical purposes taurocholate does not act as a substantial absorption modifier for cefadroxil, at least in the small intestine, the main absorption site of the antibiotic. It can, however, not be considered an inert ingredient, and therefore oral administration of cefadroxil far from that of taurocholate-containing preparations, and even from lipid-rich meals should be strongly recommended.

Algorithms↗