An evaluation of the quinolone-theophylline interaction using the Food and Drug Administration spontaneous reporting system.

A review of the Food and Drug Administration's spontaneous reporting system identified 48 reports of adverse events in patients who received concomitant therapy with ciprofloxacin (n = 39) or norfloxacin (n = 9) and theophylline. The mean (SD) age of these cases was 68.4 (18.5) years; 25 patients (52%) were female. The mean percent change in theophylline concentrations was 114%, with a range of 32% to 308% following the addition of a quinolone to the patient's theophylline regimen. Fourteen (36%) of the 39 patients receiving ciprofloxacin and three (33%) of the nine patients receiving norfloxacin experienced a seizure. The accumulated evidence suggests that extreme caution should be used when quinolones are prescribed in conjunction with theophylline, particularly in elderly patients. Further research is required to identify risk factors that will more specifically predict the magnitude of the interaction.

Comparative serum bactericidal activity of clarithromycin and azithromycin against macrolide-sensitive and resistant strains of Streptococcus pneumoniae.

The serum pharmacodynamics of clarithromycin and azithromycin were studied against isolates of S. pneumoniae, including efflux resistant (M. phenotype) strains, by analyzing their serum bactericidal activity (SBA) over time. Normal healthy subjects were given a single 500 mg oral dose of these macrolides and serum samples were collected over 12 hrs. Paired isolates with MICs ranging from 0.25 ug/ml to 8.0 ug/ml were analyzed. Prolonged (at least 6 hrs) SBA was observed with clarithromycin for strains with MICs < or = 2.0 ug/ml. No SBA was observed in strains with MICs >or = 4.0 ug/ml. Azithromycin exhibited SBA for at least 6 hrs for strains up to a MIC = 0.5 ug/ml. No SBA was observed for isolates with MICs > or = 1.0 ug/ml. In contrast to azithromycin, clarithromycin exhibited SBA for at least one-half of its normal dosing interval against S. pneumoniae strains well above its current susceptibility breakpoint concentration of 0.25 microg/ml. These findings may have relevance to the ongoing debate as to the appropriate susceptibility breakpoints for the newer macrolides.

Ampicillin/sulbactam in lower respiratory tract infections: a review.

The pathophysiology and microbiology of lower respiratory tract infections are outlined and diagnostic and therapeutic problems considered. The use of sulbactam/ampicillin in the treatment of these infections is evaluated. The two drugs have similar pharmacokinetic characteristics; predictable and dose-dependent peak serum concentrations of both agents are achieved after parenteral administration. More than 90% of strains of Staphylococcus aureus, Haemophilus influenzae, Moraxella catarrhalis, Klebsiella sp, Escherichia coli, and Acinetobacter sp were inhibited by ampicillin/sulbactam concentrations of 16/8 micrograms/ml. Serum concentrations of ampicillin and sulbactam were 18 to 28 micrograms/ml and 13 micrograms/ml, respectively, after intramuscular administration of 1 gm/0.5 gm of ampicillin/sulbactam and 58 micrograms/ml and 30 micrograms/ml, respectively, after intravenous administration of the same dose. Good distribution of ampicillin/sulbactam into lung tissue, sputum, and bronchial fluid has been demonstrated. In over 2,250 patients treated with ampicillin/sulbactam, the rate of discontinuance of treatment because of side effects was less than 1%. Satisfactory clinical and bacteriologic outcome has been reported in over 80% of patients treated with ampicillin/sulbactam. The cost of ampicillin/sulbactam treatment is generally lower than that of other comparable antibiotic regimens.

In vitro combined effect of co-amoxiclav concentrations achievable in serum after a 2000/125 mg oral dose, and polymorphonuclear neutrophils against strains of Streptococcus pneumoniae exhibiting decreased susceptibility to amoxicillin.

The in vitro effect that the presence of components of non-specific immunity (serum plus polymorphonuclear neutrophils) has on the bactericidal activity of co-amoxiclav was explored against Streptococcus pneumoniae strains exhibiting an amoxicillin MIC > or =4 mg/L. Eight penicillin-resistant clinical isolates non-susceptible to co-amoxiclav with MICs of 4 (two strains), 8 (four strains) and 16 mg/L (two strains) were used. Values of MBC were identical to MIC values in all cases. Time-kill curves were performed with co-amoxiclav concentrations achievable in serum after a single oral dose administration of the new 2000/125 mg sustained-release formulation. Results were expressed as percentage of reduction of initial inocula after 3 h incubation. Control curves showed growth with no reduction of initial inocula. Against strains with MIC of 4 and 8 mg/L, the results obtained with the antibiotic alone or with the presence of factors of non-specific immunity were similar, with a weak combined effect due to the intrinsic activity of co-amoxiclav (reductions of initial inocula ranging from 70 to 99.16%). Against strains with MIC of 16 mg/L, the addition of PMN in the presence of serum increased the reduction of bacterial load provided by the aminopenicillin, even at sub-inhibitory concentrations (25.8% versus 51.1% at 0.5 x MIC concentration--8/0.5 mg/L). This combined activity against strains with an amoxicillin MIC of 16 mg/L which decreased the bacterial load may be important in preventing bacterial proliferation within the host and the transmission of resistant clones to others.

Risk factors for arthralgias or myalgias associated with quinupristin-dalfopristin therapy.

STUDY OBJECTIVE: To evaluate risk factors for the development of arthralgias or myalgias associated with quinupristin-dalfopristin. DESIGN: Retrospective chart review and case-control analysis. SETTING: An 850-bed tertiary care medical center. PATIENTS: All adult and pediatric patients who had received quinupristin-dalfopristin through either a compassionate-use protocol (February 1996-October 1999) or in the year after quinupristin-dalfopristin was added to the hospital formulary (November 1999-October 2000) were included in this study. Case patients were those who developed arthralgias or myalgias while receiving quinupristin-dalfopristin therapy; control patients were those who received quinupristin-dalfopristin but did not develop arthralgias or myalgias. INTERVENTION: Medical records, pharmacy dispensing information, and microbiology data were reviewed by a physician and a pharmacist, both of whom specialized in infectious diseases. Presence or absence of arthralgias or myalgias was the primary outcome assessed. MEASUREMENTS AND MAIN RESULTS: Quinupristin-dalfopristin was administered to 68 patients during the period defined by the study. Arthralgias and myalgias could not be assessed in 18 of the 68 patients because they were sedated and paralyzed, or they were young children who could not communicate the presence of pain. Univariate analysis demonstrated that significant risk factors for arthralgias or myalgias associated with quinupristin-dalfopristin were female sex, chronic liver disease, receipt of liver transplant, elevated bilirubin level at baseline, major surgery, and receipt of either mycophenolate or cyclosporine. Multivariate analysis demonstrated a strong association with chronic liver disease, receipt of liver transplant, elevated bilirubin level at baseline, and receipt of either cyclosporine or mycophenolate. Of 50 evaluable patients receiving quinupristin-dalfopristin, 25 had pain that may have been associated with this antimicrobial agent. CONCLUSION: The mechanism for development of arthralgias or myalgias associated with quinupristin-dalfopristin remains unknown, but these adverse events are more likely to occur in patients with chronic liver disease and those who have received a liver transplant or are receiving cyclosporine or mycophenolate.

Risk of nephrotoxicity with combination vancomycin-aminoglycoside antibiotic therapy.

One hundred five patients receiving concurrent aminoglycoside and vancomycin therapy of at least 5 days' duration were retrospectively reviewed for development of nephrotoxicity. All had their vancomycin and aminoglycoside serum concentrations controlled by a clinical pharmacokinetics service. Nephrotoxicity occurred in 28 (27%) of the patients. Twenty-two of the 28 had other factors that are known to contribute to renal failure (amphotericin B therapy, sepsis, liver disease, obstructive uropathy, pancreatitis, anesthesia). The remaining six developed nephrotoxicity without other known contributing factors. Logistic regression analysis revealed associations between nephrotoxicity and age, sex, aminoglycoside trough and vancomycin peak and trough serum concentrations, length of aminoglycoside and vancomycin therapy, concurrent amphotericin B therapy, liver disease, neutropenia, and peritonitis (p less than 0.05). In addition to factors previously reported, this study found that neutropenia and peritonitis are associated with an increased risk of nephrotoxicity. Patients with one or more risk factors warrant close monitoring of renal function as well as vancomycin and aminoglycoside serum concentrations.

Comparison of ampicillin-sulbactam and ticarcillin-clavulanic acid in patients with chronic renal failure: effects of differential pharmacokinetics on serum bactericidal activity.

STUDY OBJECTIVES: To evaluate the pharmacodynamic antibacterial activity of ticarcillin-clavulanic acid (T-C) and ampicillin-sulbactam (A-S) combinations against reference bacterial strains in patients with end-stage renal disease maintained on long-term hemodialysis. DESIGN: Randomized, crossover, controlled study. SETTING: National Institutes of Health-funded general clinical research unit in a Veterans Administration Medical Center. PATIENTS: Nine adult men with end-stage renal disease maintained on long-term hemodialysis. Two subjects did not complete the study due to problems of vascular access, and another withdrew for personal reasons. INTERVENTIONS: On a nondialysis day, each subject was randomly administered either T-C 3.1 g or A-S 3 g as a slow intravenous infusion over 30 minutes. Serial blood samples were collected for measurement of antibiotic serum concentrations and determination of serum bactericidal titers. Following a washout period, the study was repeated with the alternative antibiotic combination. MEASUREMENTS AND MAIN RESULTS: The mean observed apparent beta-half-life of clavulanic acid was substantially shorter than that for the other three drugs. The bactericidal activity of both A-S and T-C against non-beta-lactamase-producing (N beta-LP) strains of S. aureus and E. coli was consistently high, as indicated by geometric mean SBTs of at least 1:5 at 24 hours. Against beta-lactamase-producing (beta-LP) S. aureus, the geometric mean SBTs for A-S were at least 1:25 throughout the study period, while the geometric mean SBTs for T-C decreased over 24 hours from 1:29 to 1:6. Against beta-LP E. coli, the bactericidal activities for both A-S and T-C were poor, with geometric mean peak SBTs of only 1:6 and 1:3, respectively. The geometric mean SBT for T-C against this E. coli strain had declined to 1:1 at 6 hrs. CONCLUSION: Increasing the dosing interval for T-C in patients with end-stage renal disease may lead to periods of insufficient clavulanic acid to protect ticarcillin from beta-lactamase degradation.

Amoxicillin/clavulanic acid (875/125): bioequivalence of a novel Solutab tablet and rationale for a twice-daily dosing regimen.

A new amoxicillin/clavulanic acid tablet formulation (Solutab tablet, Forcid Solutab) containing amoxicillin/clavulanic acid (875/125) has been developed. The aim of the present study was to demonstrate bioequivalence between the new tablet formulation (test), taken as an intact tablet and after prior dispersal, versus the originator product viz. Augmentan film-coated tablet (875/125) used as reference. The study was performed in 48 healthy volunteers according to an open, single-dose, crossover design. Bioequivalence was demonstrated using Cmax and AUC(0-infinity) as primary parameters of evaluation for both amoxicillin and clavulanic acid with 90% confidence intervals of the ratios Solutab tablet/Augmentan within the range of 0.8-1.25. The duration of the plasma concentration exceeding the amoxicillin minimal inhibitory concentration (MICs) was calculated using individual plasma concentration-time curves and compartmental analysis. The data showed that the bioavailability characteristics of the test tablet, taken intact or in dispersed form, and the reference tablets were very similar. The analysis, moreover, also confirmed the appropriateness of using a b.i.d. dosage regimen for both formulations, taking into account the pharmacodynamic breakpoint values for some major pathogens.

Effect of time and temperature on inactivation of aminoglycosides by ampicillin at neonatal dosages.

The administration of gentamicin at least 1 hour before administration of ampicillin in neonates has been advocated because of in vitro inactivation of aminoglycosides by beta-lactam antibiotics. This method would cause a delay in ampicillin dosing in the treatment of serious bacterial infections and unnecessarily complicate nursing procedures. We studied the effect of varying concentrations of ampicillin (50, 100, 200, and 400 micrograms/ml) on aminoglycosidic antibiotics in vitro with the use of stock solutions diluted in pooled sera obtained from cord blood and incubated samples at 25 degrees C, 37 degrees C, and 40 degrees C. We found inactivation of aminoglycosides to be dependent on time, temperature, and ampicillin concentration, but the degree of inactivation was small and does not support temporal separation of parenteral administration of ampicillin and aminoglycosides to neonates.

A pharmacodynamic model to support a 12-hour dosing interval for amoxicillin/sulbactam, a novel oral combination, in the treatment of community-acquired lower respiratory tract infections.

We evaluated, by time-kill studies, the pharmacodynamics of amoxicillin/sulbactam (AMX/SUL, 875 mg/125 mg), a novel oral combination, against the major respiratory pathogens in 12 volunteers receiving a single dose. The sera corresponding to 50% of a 12-h dosing interval displayed either bactericidal or inhibitory activity against both a penicillin-susceptible and a penicillin-intermediate Streptococcus pneumoniae strain (penicillin MIC of 0.03 and 0.25 microg/ml, respectively), as well as against a beta-lactamase-positive Moraxella catarrhalis and a beta-lactamase-negative Haemophilus influenzae strain. Both the peak samples and those corresponding to 4 h after dose (i.e. 33% of a 12-h dosing interval) proved active against both a penicillin-resistant S. pneumoniae (MIC, 2 microg/ml) and a beta-lactamase-positive H. influenzae strain. The AMX-SUL formulation evaluated in this study showed pharmacodynamic features that support clinical trials to assess its efficacy in the treatment of lower respiratory tract infections with a 12-h dosing interval regimen.

Influence of pregnancy on the pharmacokinetic behaviour and the transplacental transfer of the piperacillin-tazobactam combination.

The safety/acceptability, blood pharmacokinetics and urinary excretion of the piperacillin-tazobactam (PPR-TZB) combination were studied in six patients between 25 1/7 and 31 5/7 weeks of amenorrhea. The combination was given for a materno-fetal infection due to susceptible organisms i.e. 4/0.5 g/6 h. Whenever possible, the trans-placental transfer (TPT) of the combination was assessed in several sub-compartments of the feto-placental unit i.e. maternal blood sample, cord blood, amniotic fluid, placenta tissue and fetal urine. Two series of nine blood samples were scheduled for each patient, i.e. on D1 (first dose) and D3 (at plateau). Samples were assayed by HPLC and data were analyzed by a non-compartmental method. Safety/acceptability of the treatment proved to be good. The kinetic behavior of both beta-lactams appeared to be identical. Evidence was found during pregnancy of an increase in Vss and Cl of the combination. These increases can be linked to a notable decrease in AUCs. The TPT of the combination was significant. Regarding other accessible compartments (i.e. placenta tissue, amniotic fluid and fetal urine), the ratio of PPR-TZB concentrations was invariably about 8. Maternal circulating levels of PPR-TZB were, by 4 h, less than the MIC of target organisms (i.e. < or = 8 micrograms/ml), both on D1 and at steady state. This raises the question of the pertinence of the dosage regimen. Regarding PPR, it is accepted that antibacterial protection is satisfactory when circulating concentrations are kept at a Css (steady state concentration) of the order of 20 micrograms/ml or more. PPR-TZB combination would be administered by continuous infusion i.e. 8 mg/min to obtain 3 h later a Css of more than 20 micrograms/ml. The daily dosage would then be 12/1.5 g instead of 16/2 g, which is also more satisfactory from a pharmaco-economic standpoint. This proposal must be validated in a sufficient number of patients and, could avoid disqualification of the combination PPR-TZB in the treatment of serious infections during certain pathological pregnancies.

Biliary elimination and hepatic disposition of an association of piperacillin and tazobactam: experimental evaluation.

Biliary elimination and hepatic disposition of tazocillin, an association of a highly bile-excreted ureido-penicillin, piperacillin, with a beta-lactamase inhibitor, tazobactam, have been assessed applying an isolated perfused rabbit liver experimental model. Six investigations were performed, each during a 3 h period, using reconstituted blood circulating in a closed circuit. Piperacillin and tazobactam concentration in all specimens were determined by high performance liquid chromatography. Blood samples and cumulative bile secretion were collected every 30 min, and liver fragments were isolated at the end of each experiment for dosage purposes. Following the simultaneous administration of piperacillin 80 mg and tazobactam 10 mg (dose ratio 8/1) in the perfusion device, theoretical initial serum concentrations were respectively 414 micrograms/ml and 32.1 micrograms/ml. Maximal biliary concentrations of 4431 +/- 1541 (s.d.) of piperacillin and 21.3 +/- 7.8 micrograms/ml of tazobactam were reached between 0.5-1 h and 2.5-3 h, respectively. Cumulative biliary excretion (0-3 h) amounted to 37.6 +/- 17.7% of the administered dose for piperacillin and 1.5% for tazobactam. At the end of the perfusion, respectively 22.1% and 50.7% of piperacillin and tazobactam doses remained in the circulating blood, while 1.1% and 5.6% were found in the liver. On the basis of these data, the calculated percentages of piperacillin and tazobactam doses having undergone hepatic biotransformation, were 6.5% and 1.2%, respectively. Under such experimental conditions, concentrations and excretion of piperacillin in bile prove to be substantial. Of note, tazobactam concentrations turn out to be stable both in serum and in bile whereas they stay at a relatively constant level of 20 micrograms/ml during nearly all the perfusion time.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro bactericidal activity of peak serum concentrations of co-amoxiclav, amoxicillin and vancomycin against methicillin-resistant Staphylococcus aureus.

In order to explore the bactericidal activity of concentrations similar to the peak serum concentrations obtained after a single i.v. dose of 2,000/200 mg co-amoxiclav and 500 mg vancomycin, killing curves with co-amoxiclav (69/10 microg/ml), amoxicillin (69 microg/ml), clavulanic acid (10 microg/ml), and vancomycin (15 microg/ml) were performed against two isogenic (ss-lactamase positive and negative) methicillin-resistant Staphylococcus aureus strains in cation-supplemented Mueller-Hinton broth with 2% NaCl incubated at 35 degrees C. Colony counts were performed at 0, 1, 2, 3 and 4 hours in Mueller- Hinton plates supplemented with 4% NaCl and 25 microg/ml oxacillin to measure the resistant population. Similar initial inocula reductions were obtained for amoxicillin-clavulanic acid and vancomycin for both strains, and significant differences were found in comparison to the control. Clavulanic acid decreased the growth rate of the ss-lactamase negative strain when compared to control curves. The penicillin-binding protein 2a affinity of old ss-lactams in conjunction with clavulanic acid overcoming ss-lactamase resistance may explain these results.

Disposition of penicillin G after administration of benzathine penicillin G, or a combination of benzathine penicillin G and procaine penicillin G in cattle.

Plasma concentration of penicillin G was evaluated in beef steers after administration of either a combination of benzathine penicillin G and procaine penicillin G in a 1:1 mixture at a dosage of 9,000 U/kg of body weight, IM (n = 5), 24,000 U/kg, IM (n = 5), or 8,800 U/kg, SC (n = 5), or benzathine penicillin G alone at a dosage of 12,000 U/kg, IM (n = 7). Plasma concentration of penicillin G was measured by use of a high-performance liquid chromatography assay that had a limit of determination of 0.005 microgram/ml. At a dosage for this combination of 9,000 U/kg IM, and 8,800 U/kg, SC, which are approved label recommendations in Canada, and the United States, respectively, mean (+/- SEM) peak plasma concentration was 0.58 (+/- 0.15) and 0.44 (+/- 0.02) microgram/ml, respectively. Although plasma penicillin concentration was quantifiable for 7 days in the steers that received 9,000 U/kg, IM, and for 4 days in the steers that received 8,800 U/kg, SC, the concentration was < 0.1 microgram/ml in both groups after the first 12 hours. After administration of the combination at dosage of 24,000 U/kg, IM, there was an initial peak plasma concentration at approximately 2 hours; thereafter, plasma concentration decreased slowly, with half-life of 58 hours. Although plasma penicillin G concentration was quantifiable for 12 days at this dosage, concentration was < 0.1 microgram/ml after the first 48 hours. After the initial 48 hours, plasma concentration of penicillin was of similar magnitude and decreased at similar rate for the combination at dosage of 24,000 U/kg and for 12,000 U/kg of benzathine penicillin G alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Variable absorption of clavulanic acid after an oral dose of 25 mg/kg of Clavubactin and Synulox in healthy cats.

The aims of this investigation were to calculate the pharmacokinetic parameters and to identify parameters, based on individual plasma concentration-time curves of amoxicillin and clavulanic acid in cats, that may govern the observed differences in absorption of both drugs. The evaluation was based on the data from plasma concentration-time curves obtained following a single-dose, open, randomised, two-way crossover phase-I study, each involving 24 female cats treated with two Amoxi-Clav formulations (formulation A was Clavubactin and formulation was B Synulox; 80/20 mg, 24 animals, 48 drug administrations). Plasma amoxicillin and clavulanic acid concentrations were determined using validated bioassay methods. The half-life of elimination of amoxicillin is 1.2 h (t1/2 = 1.24 +/- 0.28 h, Cmax = 12.8 +/- 2.12 microg/ml), and that of clavulanic acid 0.6 h (t1/2 = 0.63 +/- 0.16 h, Cmax = 4.60 +/- 1.68 microg/ml). There is a ninefold variation in the AUCt of clavulanic acid for both formulations, while the AUCt of amoxicillin varies by a factor of two. The highest clavulanic acid AUCt values indicate the best absorption; all other data indicate less absorption. Taking into account that the amoxicillin-to-clavulanic acid dose ratio in the two products tested was 4:1, the blood concentration ratios may actually vary much more, apparently without compromising the products" high efficacy against susceptible microorganisms.

An investigation into the effect of traumatically produced cerebrospinal fluid fistulae on the passage of Augmentin across the blood-brain barrier.

In the management of cerebrospinal fluid (csf) fistulae, associated with head and facial injury, prophylactic antimicrobial drugs are employed commonly to prevent the occurrence of bacterial meningitis. Under normal circumstances, penicillins achieve a low csf/plasma concentration ratio, but trauma may reduce the efficacy of the blood-brain barrier and permit increased amounts of penicillins to enter the csf. To test this hypothesis, with respect to Augmentin (amoxycillin and clavulanic acid), an animal study was undertaken. Under general anaesthesia, the brains and meninges of a group of 10 rabbits were traumatised to produce csf fistulae. Following the administration of an intravenous bolus of Augmentin, the blood and csf concentrations of Augmentin were measured over a period of 6 h and compared with those measurements from an untraumatised control group of 10 rabbits. No difference in the csf/plasma ratio was apparent between the two groups. The results of this study, therefore, suggest that trauma to the brain and meninges does not increase the permeability of the blood-brain barrier to Augmentin.

[Penetration of potassium clavulanate/ticarcillin sodium into cerebrospinal fluid in neurosurgical patients].

Concentrations of potassium clavulanate (CVA) and ticarcillin sodium (TIPC) in the plasma and cerebrospinal fluid (CSF) of patients after neurosurgical intervention were determined at various times after a 1-hour drip infusion (3.2-g dose). Patients whose blood-brain barriers were supposed to be maintained in almost a normal condition were selected. CSF was obtained through a catheter placed in the anterior horn of the lateral ventricle in all the patients. Maximum plasma levels (micrograms/ml) of 57.6 to 384.0 with an average of 169.7 (TIPC) and 0.41 to 26.2 with an average of 6.1 (CVA) were achieved at the termination of infusion. The maximum CSF levels (micrograms/ml) were 0.61 to 18.8 (TIPC) and 0.1 to 6.81 (CVA) with mean values of 4.5 and 1.2, respectively. Plasma half lives (T1/2) (minute) were 24 to 93 (TIPC) and 32 to 227 with mean values of 58 and 127, respectively. The mean values of the CSF half lives (minute) were 237 (TIPC) and 113 (CVA). The ratios (%) of CSF levels to plasma levels in maximum concentration (Cmax), AUC (area under concentration curve) and half life (T1/2) were calculated. Cmax ratios were 0.2 to 29.2 (TIPC) and 1.4 to 69.8 (CVA) with mean values of 4.4 and 22.8, respectively. AUC ratios were 0.3 to 23.5 (TIPC) and 1.1 to 70.2 (CVA) with mean values of 4.3 and 22.4, respectively. T1/2 ratios were 1.3 to 18 (TIPC) and 1.1 to 4.3 (CVA) with mean values of 5.5 and 2.3, respectively. These values indicate that CVA/TIPC may be classified into a group of antibiotics with good penetration into the CSF.

[Cerebrospinal fluid levels of sulbactam/ampicillin in rabbits with staphylococcal meningitis].

Concentrations of sulbactam (SBT) and ampicillin (ABPC) in the blood and cerebrospinal fluid (CSF) following an intravenous administration of SBT/ABPC at a dose of 150 mg/kg (SBT/ABPC = 1:2) were determined in 12 rabbits with staphylococcal meningitis. Drug concentrations were measured 9 times, 6 times each with intervals of 15 minutes and thereafter with intervals of 30 minutes. The results were compared with those of a group of 9 rabbits given 100 mg/kg of ABPC alone. 1. The maximum concentration of SBT in the CSF and the percentages of both the maximum concentration and the area under the concentration-time curve (AUC) of SBT in CSF vs. those in serum of the SBT/ABPC group were higher than those of ABPC and the half-life of SBT in the CSF was also longer than that of ABPC, all with significant difference. When these parameters for SBT of SBT/ABPC groups were compared with those of ABPC of the ABPC group, not much differences existed between the 2 groups except that the CSF half-life of SBT was much longer than that of ABPC. 2. The percentages of both the maximum concentration and AUC of ABPC in CSF vs. those in serum of the SBT/ABPC group were significantly lower than those of ABPC of the ABPC group. The CSF half-life of ABPC of the former group was longer than that of the latter. 3. The above results suggest that when SBT and ABPC are administered simultaneously, the penetration of ABPC into the CSF is inhibited.

[Pharmacokinetic, bacteriological, and clinical studies on panipenem/betamipron in children].

Pharmacokinetic, bacteriological and clinical studies were performed on panipenem/betamipron (PAPM/BP) in children. The results are summarized as follow: 1. Twelve patients with various bacterial infectious diseases were treated with PAPM/BP. Each dose was 20 mg/20 mg/kg, administered 3 times daily, in 30-minute intravenous drip infusion. Treatments were continued for 5-22 days. Clinical efficacies of PAPM/BP in 12 patients with bacterial infections (1 with suspected sepsis, 5 with pneumonia, 1 with acute maxillary sinusitis, 2 with acute otitis media, 1 with cervical abscess and 2 with urinary tract infection complexed type) were evaluated as excellent in 7, good in 4 and fair in 1, with an efficacy rate of 91.7%. Seventeen causative organisms found in 10 patients (Haemophilus influenzae in 4, Branhamella catarrhalis in 3, Streptococcus pneumoniae in 2, Pseudomonas aeruginosa in 2, Staphylococcus aureus in 1, alpha-Streptococcus in 1, Corynebacterium sp. in 1, Peptostreptococcus micros in 1 and Klebsiella pneumoniae in 2) were eradicated except 2 strains (S. aureus and P. aeruginosa) from 1 patient (patient No. 2). No adverse reactions were observed in any of the 12 patients. 2. MICs of PAPM were examined against 22 clinical isolates (H. influenzae 5, B. catarrhalis 3, alpha-Streptococcus 3, S. pneumoniae 2, Corynebacterium sp. 2, S. aureus 1, P. aeruginosa 1, P. micros 1, Enterobacter cloacae 1, Escherichia coli 1, Group D Streptococcus 1 and Staphylococcus epidermidis 1) from children with bacterial infections. PAPM showed a good antibacterial activity comparable to the activity of cefoperazone (CPZ) against S. pneumoniae strains relatively tolerant to penicillins. However, the activity of PAPM against H. influenzae was somewhat weaker than that of CPZ. 3. Pharmacokinetic studies.(ABSTRACT TRUNCATED AT 250 WORDS)

[Clinical evaluation of panipenem/betamipron in children].

Panipenem/betamipron (PAPM/BP), a new injectable carbapenem antibiotic, was evaluated for its safety and efficacy in children. Ninety three percentage (14 in 15 cases) of various infections were cured with PAPM/BP therapy. Transient skin rash occurred in 1 case, probably due to the histamine-like effect of PAPM/BP. The plasma half life of panipenem was 0.85 +/- 0.07 hours. PAPM/BP was evaluated to be a less-epileptogenic carbapenem antibiotic.