Pharmacokinetics of oral cefatrizine in pregnant and non-pregnant women with reference to fetal distribution.

OBJECTIVE: To investigate the effect of gestation on the pharmacokinetics of orally administered beta-lactams, choosing cefatrizine as the model antibiotic. SETTING: A tertiary teaching hospital. DESIGN: Prospective study. METHODS: In 20 women with affected fetuses, 17 by beta-thalassemia major and 3 with congenital malformations, termination of gestation between 19 and 24 weeks was induced by intra-amniotic administration of prostaglandin F(2)(alpha). Pharmacokinetics of cefatrizine in maternal and fetal blood were studied after the administration of three 1 g doses of oral cefatrizine, every 12 h. Twenty female non-pregnant volunteers consisted the control group. RESULTS: Gestation was found to decrease substantially both cefatrizine oral bioavailability and maximum serum plasma concentration (42.8 and 44.5%, respectively) but increased elimination half-life. This effect can be attributed to a substantial increase of the apparent volume of distribution of cefatrizine in relation to a moderate increase of clearance that occurs during pregnancy. Fetal serum cefatrizine levels were lower for the first few hours after administration and then exceeded the corresponding maternal ones. CONCLUSIONS: Our results indicate that gestation decreases the oral bioavailability of cefatrizine. A delay in the maternal drug elimination compared to non-pregnant controls was more pronounced in the fetus.

Dose dependency in the gastrointestinal absorption of cefatrizine: correlation between in vivo and in situ.

We evaluated the dose-dependent (saturable) gastrointestinal absorption of cefatrizine, an aminocephalosporin transported by peptide carriers, in rats by a physiological mechanism-based approach to clarify its absorption characteristics and to examine the in vitro (in situ)-in vivo correlation in intestinal transport. With an increase in oral dose (mumol/5 ml/kg) from 5 (low) to 50 (high), the intestinal absorption rate constant (ka), which was estimated by analysis of gastrointestinal disposition, decreased markedly, from 0.301 to 0.056 min-1. This decrease was ascribable to the saturability of intestinal membrane transport, of which the concentration dependency in the perfused intestine was similar in extent to the dose dependency in ka. However, the apparent absorption rate constant (ka'), which was estimated by analysis of plasma concentrations after oral administration, decreased only modestly from 0.037 to 0.023 min-1. This was associated with the result that, at the low dose, ka' was far smaller than ka and comparable with k(g) (gastric emptying rate constant), suggesting gastric emptying-limited absorption. At the high dose, where intestinal cefatrizine absorption was less efficient, ka' was closer to ka than k(g). It was also observed that the bioavailability was close to unity, independent of dose, suggesting that the intestinal transit time is long enough to achieve complete absorption, even at the high dose, where intestinal cefatrizine absorption is less efficient. Thus, it was found that the effect of saturability in the intestinal transport of cefatrizine is apparently attenuated in its overall gastrointestinal absorption because of the involvement of gastric emptying and intestinal transit time as additional physiological factors to define absorption. It was also found that a scaling factor is required to correlate the intestinal membrane transport between in vitro (in situ) and in vivo, though this remains to be verified to be utilized for developing oral drug delivery strategies and optimizing oral drug therapy.

[Comparative trial of the clinical efficacy and tolerance of cefatrizine (Cefaperos) and cefpodoxime proxetil (Orelox) in superinfections of chronic obstructive bronchopneumopathies in adults in urban practice]. / Essai comparatif de l'efficacité et de la tolérance clinique entre la céfatrizine (Cefaperos) et le cefpodoxime proxétil (Orelox) dans les surinfections des bronchopneumopathies chroniques obstructives de l'adulte en médecine de ville.

In order to compare the clinical efficacy and safety of cefatrizine (Cefaperos) and cefpodoxime proxetil (Orelox) in the treatment of secondarily infected chronic obstructive pulmonary disease (COPD) in adults, a multicentre, randomized, open study was conducted by 60 general practitioners in two parallel groups of patient suffering from COPD complicated by an acute episode of superinfection (Anthoniesen stages 2 and 3). After verification of the eligibility criteria, written consent and randomization, the patients received, for 10 days, either cefatrizine at the dose of 1 g/day or cefpodoxime proxetil at the dose of 400 mg/day. A self-assessment form was given to the patient. A telephone visit was planned for D3. The final visit on D11 +/- 1 evaluated clinical efficacy (success or failure) and safety. The study population was composed of 250 patients with a mean age of 59.9 +/- 15.9 years (sex ratio M/F = 1.5). The principal etiology of COPD was chronic bronchitis in 67.5% of patients, longstanding asthma in 24.5% and emphysema in 6.8%. The mean history of the disease was 13.0 +/- 10.8 years. The Anthoniesen score was equal to 2 in 73.6% of patients, 3 in 8.8% of patients and 1 in 17.6% of patients. No significant difference concerning these criteria was observed between the two study groups. The clinical success rate was equivalent in the two groups. The time to regression of clinical signs tended to be shorter, up until the sixth day (mainly between D4 and D6) for patients treated with cefatrizine (p = 0.09; NS). The clinical safety was considered to be good and was comparable in the two study groups. This study concluded on the equivalent clinical efficacy of cefatrizine and cefpodoxime proxetil in the treatment of superinfections of COPD in general practice (97.5% and 99%, respectively), with a satisfactory and comparable safety, but with a much lower cost of treatment for cefatrizine. This conclusion is particularly important in the context of opposable medical references, as, although the treatment of superinfections of COPD by second and third generation cephalosporins is frequently proposed, the prescription of a less expensive cephalosporin appears to be more relevant.

Pharmacokinetics of oral cefatrizine in patients with impaired renal function.

The pharmacokinetics of cefatrizine was studied in 15 patients with various degrees of renal impairment, after single oral administration of 500 mg. Cefatrizine elimination was reduced in parallel to renal function, as indicated by the significant correlations between apparent clearance (Cl/F) and creatinine clearance (Clcr), and between renal clearance (Clr) and creatinine clearance (Clcr). In patients with totally impaired renal function, the residual clearance (Cl/F) was 63 ml.min-1 per 1.73 m2. Comparisons with previously published data indicate that the apparent volume of distribution (V/F) of cefatrizine was lower in patients with impaired renal function than in young healthy volunteers, leading to increased peak concentrations (Cmax), but there was no relationship between V/F and Clcr. In patients with totally impaired renal function, the upper limit of cefatrizine elimination half-life was estimated to 5.5 h. The clinical significance of pharmacokinetic modifications observed in renal disease patients may only be realized through integration of pharmacodynamic characteristics of cefatrizine. The observed increase in Cmax and the lengthening of t1/2 could suggest a reduction of dosing frequency in patients with severe renal impairment.

Saturable rate of cefatrizine absorption after oral administration to humans.

This study examined the absorption kinetics of cefatrizine, an amino-beta-lactam antibiotic, after oral administration of a single 500-mg dose to 12 healthy volunteers. Plasma concentrations were determined by high performance liquid chromatography. The plots of the percentage of drug unabsorbed and the apparent rate of cefatrizine absorption as a function of time showed, first, a delay and, then, an almost constant rate of absorption with a tendency to move toward first-order kinetics at the end of the process. Three compartmental models incorporating a lag time and first-order elimination kinetics, but differing in their input rate, were used for analysis of the time course of cefatrizine plasma concentrations. The model with first-order absorption kinetics was clearly inadequate. The results were improved with the model for which the rate of absorption is constant, but a model incorporating saturable absorption kinetics of the Michaelis-Menten type improved the fit further. This last model was statistically superior to the constant-rate input model in 6 out of 12 subjects, according to the likelihood-ratio method. Because of the innovative feature of the model incorporating the Michaelis-Menten equation, simulations of the effect of altering the model parameters and the dose administered on the concentration-time profile, were performed. Different hypotheses which might explain why cefatrizine absorption kinetics fits the Michaelis-Menten equation were examined. The observation of saturable absorption kinetics is consistent with a carrier-mediated transport previously reported to occur in the gastrointestinal tract of rats.

[Pharmacokinetics of cefatrizine administered in repeated doses]. / Pharmacocinétique de la céfatrizine administrée en doses répétées.

Twelve healthy volunteers received cefatrizine orally at doses equal to 500 mg every 12 h for 5 days. Cefatrizine was assayed by high performance liquid chromatography in plasma and urines collected after the first and/or the last administration. Cefatrizine absorption was rapid; its peak plasma level was reached at time 1.79 +/- 0.07 h following the first dose, it was equal to 7.37 +/- 0.31 micrograms.ml-1. Its apparent elimination half-life was equal to 1.50 +/- 0.05 h, it explains the lack of accumulation with time during multiple administrations every 12 hours. Comparisons between peak plasma concentration and area under curves following the first and last dosing showed significant (p less than 0.01) but weak (close to 15%) reduction of these 2 parameters with time which could be explained by a slight reduction of cefatrizine absorption with time. In conclusion, cefatrizine does not accumulate when administered repeatedly at a dose equal to 500 mg every 12 h in young adult, and its pharmacokinetics is virtually linear with time.

A double-blind clinical comparison of two dosage schedules of cefatrizine in children.

A double-blind, randomized clinical trial was carried out to compare the effectiveness of twice daily versus once daily administration of the cephalosporin, cefatrizine, in paediatric outpatients with bacterial infection of the respiratory tract. Thirty children were studied, aged 7 years 2 months (range, 4-12 years). They were given 75 mg/kg.day cefatrizine either once daily or twice daily at 12 h intervals for 8 days. Fever, clinical symptoms, bacterial eradication and overall tolerance were evaluated. No significant differences were observed between once daily or twice daily administration. This is in agreement with other studies carried out on adults. It is concluded that cefatrizine may be given to paediatric out-patients for the treatment of bacterial infection of the respiratory tract only once daily with good clinical and overall results.

Controlled multicenter clinical comparison between two cefatrizine administration schedules: a contribution to improvement of compliance in clinical nonhospital use of antibiotics.

Eight Italian clinical centers carried out a controlled double-blind/double-dummy evaluation of the effectiveness of two different administration schedules of cefatrizine, an orally active cephalosporin. The first schedule provided for once-a-day administration of 1.5 gm of the drug, and the second one for twice-a-day administration of 0.75 gm. The trial included 160 patients affected by bacterial diseases of the respiratory apparatus. The two drug administration schedules were found to be equivalent in clinical and bacteriological results and in tolerability.

Clinical pharmacokinetics of five oral cephalosporins in calves.

The minimal inhibitory concentrations (MIC) of cephalexin, cephradine, cefaclor, cefatrizine and cefadroxil for Salmonella species, Escherichia coli and Pasteurella multocida isolated previously from young calves were determined. The MIC90 values for cephalexin, cephradine and cefadroxil ranged between 3.12 micrograms ml-1 and 12.5 micrograms ml-1, whereas those of cefatrizine and cefaclor were 3.12 micrograms ml-1 and 0.78 microgram ml-1, respectively. Each drug was administered intravenously and orally to groups of pre-ruminating calves and orally to early ruminating calves. Although the pharmacokinetic characteristics of the drugs after intravenous injection were similar to other beta-lactam antibiotics, significant differences between the cephalosporins examined were found in respect of certain kinetic parameters. The drugs showed rapid absorption into the systemic circulation after oral administration to pre-ruminating calves but the elimination half-life values (t1/2 beta) varied between three hours (cefaclor and cefadroxil) and nine hours (cefatrizine). The bioavailability of the drugs was about 35 per cent of the administered dose. Co-administration of probenecid with each antibiotic caused a twofold or greater increase in peak serum drug concentrations (Cmax) but the effect on t1/2 beta was variable. Cephalexin, cephradine and cefaclor given to the ruminating calves resulted in very low serum or plasma concentrations and their use should be restricted to younger calves. Cefadroxil was found to give the highest serum concentrations in this age group but had significantly lower bioavailability when compared with the unweaned calves. Provisional oral dosage regimens were computed for each cephalosporin on the basis of the MIC data and the kinetic parameters derived from intravenous and oral drug administration.

Kinetics of cefatrizine penetration into gynaecological tissues after oral administration.

Twenty-four patients, hospitalized in order to undergo radical gynaecological surgery, were orally administered cefatrizine in a single dose of 1 g at different times before surgery. The tissue levels determined in the organs considered (uterus, ovary, tubae, vagina) proved that cefatrizine possesses good absorption in the genital tract, reaching concentrations near to the MICs of most gram-negative and gram-positive sensitive bacteria lasting even 12 h after administration.

Cefatrizine: a clinical overview.

Cefatrizine, a new oral cephalosporin, proved effective in the treatment of a wide range of bacterial infections in both adult and paediatric patients. Adverse reactions mild and mainly limited to gastrointestinal disturbances.

Pharmacokinetics of cefatrizine after oral administration in human volunteers.

The oral bioavailability of cefatrizine was studied in four groups, each of ten healthy young male volunteers. Capsules and suspension formulations were each administered at doses of 250 and 500 mg. Both the capsules and suspensions had mean peak plasma levels at 1.6 h at both dose levels. Mean peak plasma levels were 4.1 and 4.3 micrograms/ml for the 250 mg capsule and suspension doses respectively and 7.1 and 7.5 micrograms/ml for the 500 mg capsules and suspension doses respectively. The overall mean half-life was 1.7 h. For both types of formulations and at both dose levels 63-65% of the doses were excreted in the urine as intact cefatrizine, 85% of this amount within 8 h. The overall mean renal clearance was 157 ml/min. The cefatrizine capsule and suspension formulations were completely bioequivalent in regard to both rate and extent of bioavailability. Plasma concentrations and urinary recoveries of cefatrizine were higher than those previously reported, due to precautions taken in sample collection and storage.

Human intravenous pharmacokinetics and absolute oral bioavailability of cefatrizine.

Cefatrizine was administered intravenously and orally at dose levels of 250, 500, and 1,000 mg to normal male volunteers in a crossover study. Intravenous pharmacokinetics were dose linear over this range; mean peak plasma concentrations at the end of 30-min infusions were, respectively, 18, 37, and 75 micrograms/ml, total body clearance was 218 ml/min per 1.73 m2, renal clearance was 176 ml/min per 1.73 m2, and mean retention time in the body was 1.11 h. Cumulative urinary excretion of intact cefatrizine was 80% of the dose, and half-lives ranged from 1 to 1.4 h. Steady-state volume of distribution was 0.22 liters/kg. On oral administration, the absolute bioavailabilities of cefatrizine were 75% at 250 and 500 mg and 50% at 1,000 mg. The mean peak plasma concentrations and peak times were, respectively, 4.9, 8.6, and 10.2 micrograms/ml at 1.4, 1.6, and 2.0 h, mean residence times were 2.4, 2.6, and 3.1 h, and mean absorption times were 1.3, 1.6, and 1.9 h. Oral renal clearance and half-life values corresponded well to the intravenous values. Cumulative urinary excretion of intact cefatrizine (as percentage of dose) was 60 at 250 mg, 56 at 500 mg, and 42 at 1,000 mg. It is hypothesized that the lack of oral dose linearity between the 500- and 1,000-mg doses is due to a component of cefatrizine absorption by a saturable transport process. Relative absorption at the high dose would be sufficiently slow that an absorption "window" would be passed before maximum bioavailability could be attained. It is not expected that the observed bioavailability decrease at doses exceeding 500 mg will have any therapeutic significance, since clinical studies are establishing efficacy for a recommended unit dosage regimen of 500 mg.