Serum and dialysate concentrations of cephalexin following repeated dosing in CAPD patients

Oral cephalexin, 1 to 2 g daily for 3 days, was given to six stable, noninfected patients receiving maintenance continuous ambulatory peritoneal dialysis (CAPD). The peak serum concentration after a 2 g initial dose was between 73 and 123 mg/L. On the second and third day in five patients who received a 2 g daily oral dose, the serum concentrations were between 35 and 118 mg/L in serum obtained 1 to 1.5 hours after the dosing. Similar serum concentrations were seen in one patient who only received a 1 g oral dose on the second and third day. Cephalexin concentrations in the peritoneal dialysate reached a peak on the first day between 4 to 14 hours after the dose and were between 31 to 78 mg/L. During the second and third day, the highest cephalexin concentration was 118 mg/L and the lowest was 12 mg/L. The data are consistent with the feasibility of oral cephalexin for treatment of CAPD-associated peritonitis with microorganisms that are sensitive to these levels of cephalexin.     

Treatment of gram-positive peritonitis with two intraperitoneal doses of vancomycin in continuous ambulatory peritoneal dialysis patients

Eight patients with end-stage renal failure on continuous ambulatory peritoneal dialysis (CAPD), who developed peritonitis, received an intraperitoneal dose of vancomycin (30 mg/kg body weight) with 6 h of peritoneal dwell and then resumed their routine CAPD schedule. Vancomycin concentration in serum, peritoneal dialysate (PD) from an overnight dwell and 1, 2 and 3 h after a new exchange was measured at 48 h (in 5 patients) and 7 days (in 6 patients). Except for an occasional 1-hour peritoneal fluid sample on the 7th day, all samples had satisfactory vancomycin levels. Five of the 8 patients who had gram-positive peritonitis and 1 with 'sterile' peritonitis received another similar intraperitoneal dose of vancomycin at the 7th day. All of these patients had good therapeutic response with a negative PD culture 3 weeks after the cessation of therapy and no relapse of infection in at least 1 month of follow-up. We conclude that 2 intraperitoneal doses of vancomycin (30 mg/kg body weight) given 1 week apart with 6 h of intraperitoneal dwell is an effective and adequate treatment for gram-positive and 'sterile' peritonitis in CAPD patients.     

Trimethoprim-sulfamethoxazole pharmacokinetics during continuous ambulatory peritoneal dialysis

Eight adult patients without peritonitis maintained on chronic ambulatory peritoneal dialysis (CAPD) were administered a single oral dose of 320 mg trimethoprim (TMP) and 1600 mg sulfamethoxazole (SMX) to characterize the pharmacokinetics of TMP and SMX. Ten blood samples were drawn following the dose. TMP and SMX-active (SMXA) concentrations were quantified in serum and dialysate. The half-life of TMP and SMXA determined by model independent methods were 33.7 +/- 10.5 h (mean +/- SD) and 13.8 +/- 2.2 h respectively. Total body clearance of TMP was 32.8 +/- 10.1 ml/min and SMXA was 21.9 +/- 6.4 ml/min. CAPD clearance of TMP was 2.27 +/- 0.81 ml/min and SMXA was 1.72 +/- 0.93 ml/min. The average peritoneal dialysate concentrations over the 72-hour collection period of TMP and SMXA were 0.9 +/- 0.1 mg/l and 5.3 +/- 0.8 mg/l respectively. A dose of 320 mg TMP and 1600 mg SMX every 48 hours is recommended for CAPD patients with mild to moderate systemic infections.     

Leptin in CAPD patients: serum concentrations and peritoneal loss.

BACKGROUND: To determine whether serum leptin concentrations in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) are influenced by peritoneal loss of leptin and to compare serum leptin levels of normal subjects with those of patients receiving renal replacement therapy such as haemodialysis (HD), CAPD, or kidney transplantation. SUBJECTS AND METHODS: Eighty-four individuals were investigated: six females and 14 males on standard CAPD; 13 females and 13 males on chronic HD; 10 female and eight male kidney transplant recipients, and 10 female and 10 male subjects as controls. Morning serum, 8-h and 24-h samples of peritoneal fluid concentrated to 6-20-fold by Centricon 3 (cutoff 3000 daltons), and 24-h urinary concentrations of leptin were measured with commercial RIA (Linco Research, Inc., USA). Venous blood and peritoneal fluid samples of albumin, beta2-microglobulin, glucose, urea, and creatinine were determined by standard laboratory techniques. Serum insulin levels were measured by radioimmunoassay. RESULTS: Patients (men and women) on CAPD and after kidney transplantation exhibited significantly higher serum concentrations of leptin and leptin/BMI ratios than control subjects. These increased values did not reach statistical significance in HD patients. Serum leptin concentrations were correlated very significantly with BMI in all cases (r=0.380, P<0.001). Moreover, in CAPD patients (r=0.630, P<0.007) and in HD patients (r=0.668, P<0.005), but not in kidney transplant recipients or control subjects, significant correlations were observed between serum leptin and insulin concentrations. Residual renal function (RRF) in the range 0-12.8 ml/min and serum beta2-microglobulin levels in the range 7.9-47.1 mg/l did not influence serum leptin levels in CAPD and HD patients. As expected, leptin was detected in the peritoneal fluid of CAPD patients. Twenty-four-hour peritoneal loss (30.95+/-21.05 ng/min) and 24-h peritoneal clearance (0.01+/-0.01 ml/kg/min) of leptin account for only 3.9% of estimated whole-body leptin production rate and 0.7% of leptin clearance from plasma respectively. Twenty-four-hour urinary losses of leptin in CAPD patients were negligible, accounting for 5.6+/-1.8% (range 0.3-15.2%) of total (peritoneal and urinary) loss of this hormone. CONCLUSIONS: These findings suggest that serum leptin levels are not affected by continuous peritoneal loss of leptin during CAPD and that insulin resistance and hyperinsulinaemia contribute to elevated serum leptin concentrations in CAPD and HD patients. The aetiology of increased serum leptin levels in kidney transplant recipients is probably different from that in dialysis patients.     

Losses of 1,25- and 24,25-dihydroxycholecalciferol in the peritoneal fluid of patients treated with continuous ambulatory peritoneal dialysis

We measured peritoneal losses of the active vitamin D metabolites 1,25(OH)2D3 and 24,25(OH)2D3 in patients receiving continuous ambulatory peritoneal dialysis (CAPD). The serum concentration of 24,25(OH)2D3 was considerably lower than in hemodialysis patients. The serum concentration of 1,25(OH)2D3 was undetectable and rose to levels similar to those in hemodialysis patients only after loading with much higher oral doses of 1-alpha-vitamin D3 than those received by hemodialysis patients. Losses of both metabolites in peritoneal fluid were considerable, averaging approximately 6-8% of the plasma pool per day. These losses lead to low serum levels of these active vitamin D metabolites in CAPD patients, which may be an important factor in exacerbating renal osteodystrophy. Our results indicate the need for increased replacement doses of vitamin D metabolites in CAPD patients.     

High serum D-lactate in patients on continuous ambulatory peritoneal dialysis

Background. As abnormally high serum D-lactate levels may cause nephrological impairment, we determined whether patients undergoing continuous ambulatory peritoneal dialysis (CAPD) with lactate-containing fluids have increased serum D-lactate concentrations. Methods. D- and L-lactate concentrations were determined in peritoneal dialysis fluids and in serum from control subjects (n = 10), haemodialysis patients (n = 10), and CAPD patients (n = 30) before and after 1 h of dialysis. Results. We found the median D-lactate concentration in Dianeal CAPD fluid to be 26 mM (range 19-27), whereas it was less than 0.5 mM in DPCA2 fluid. Control, haemodialysis, and CAPD (DPCA2) patient median serum D-lactate concentrations were below 0.07 mM. However, CAPD (Dianeal)_patient serum D-lactate concentrations were 4-fold higher than controls (P <0.0001), at 0.28 mM, an hour after instillation of D-lactate-containing fluid. Three patients, whose serum D-lactate averaged 0.59 mM, were found to have D-lactate concentrations at 0.22 mM after overnight cessation of dialysis. Conclusion. We conclude that CAPD with D-lactate-containing fluids raises serum D-lactate to abnormal levels.     

Behavior of beta 2-microglobulin in patients with chronic renal failure undergoing hemodialysis, hemodiafiltration and continuous ambulatory peritoneal dialysis (CAPD)

beta 2-microglobulin (beta 2-m) is the major component of a new form of amyloid deposit found in carpal tunnel syndrome and dialysis arthropathy of long-term hemodialysis patients. In 52 patients on maintenance hemodialysis, serum beta 2-m concentration was elevated to 37.9 +/- 1.4 (normal 1.2 +/- 0.6) mg/l. It was correlated with the time on hemodialysis (r = 0.43, p less than 0.01) and was inversely correlated with residual renal function (r = 0.87, p less than 0.001). In 20 patients on CAPD, beta 2-m likewise was increased to 31.6 +/- 2.3 mg/l; daily elimination by dialysate was only 34 mg (normal 150 mg). Hemodialysis with a cuprophane membrane caused a rise in serum beta 2-m, whereas hemodiafiltration with a polysulfone membrane performed in 5 patients over 2 1/2 months was accompanied by a decrease in serum beta 2-m from 39.5 +/- 0.7 to 29.7 +/- 1.0 mg/l predialysis (19.1 +/- 1.1 postdialysis). On the other hand, beta 2-m elimination reached only approximately 100 mg per day in spite of markedly elevated serum levels. It is concluded that serum beta 2-m is massively elevated in long-term hemodialysis and CAPD patients; contrary to routine hemodialysis with cuprophane membranes, newer more permeable membranes will permit some elimination of beta 2-m. However, based on quantitative considerations it seems difficult to obtain beta 2-m concentrations in the high normal or moderately elevated range with present day techniques.     

Oral Treatment of Peritonitis in CAPD Patients with Ofloxacin

Eighteen episodes of peritonitis in 16 CAPD patients were treatedwith oral ofloxacin 400 mg initially. followed by 300 mg dailyfor a total of 10 days. The culture-positive rate was 72.2%with Staphylococcal species as the most frequent isolates. Theoverall cure rate as defined by negative cultures 1 and 2 monthsafter discontinuation of antibiotics was 83.3%. The time takenfor the peritoneal effluent to clear completely was 5 days.With such a dosing regime, there was a significant increasein the mean serum trough level of ofloxacin from 2.28 mg/1 onday 1 to 5.83 mg/1 on day l0(P<0.001). There was no significantdifference in the serum levels attained whether or not phosphatebinders were concurrently given. Sideeffects were nausea andnon-specific dizziness. No patients had to discontinue treatmentbecause of sideeffects. Ofloxacin appeared to diffuse from theblood into the peritoneal fluid, and a highly significant correlationexisted between simultaneous blood and peritoneal effluent ofloxacinlevels (r=0.88, P<0.000l).     

Intraperitoneal penetration of pefloxacin in patients on continuous ambulatory peritoneal dialysis

Summary: Six patients with continuous ambulatory peritoneal dialysis (CAPD) associated peritonitis were treated with oral pefloxacin 400 mg twice a day. the concentration of pefloxacin was assayed in 20 sets of serum and peritoneal dialysate samples taken from these patients. With a mean starting serum level of 7.6 mg/L, pefloxacin was detected in all peritoneal dialysates within 15 min and attained a mean concentration of 4.2 mg/L within 2 h. the percentage penetration of pefloxacin into peritoneal fluid was 72.9% (SD 19.4%). the results showed that the administration of oral pefloxacin 400 mg b.d. could result in peritoneal drug levels that should be adequate for the treatment of peritonitis caused by common pathogens like Enterobacteriaceae species and Staphylococcus aureus. However, it may be necessary to give the drug parenterally on the first day of treatment before steady-state plasma concentrations are achieved and, in empirical therapy, combination antibiotics may be required when infection by more resistant pathogens is suspected.     

Plasma oxalate in patients with chronic renal failure receiving continuous ambulatory peritoneal dialysis or hemodialysis

Plasma oxalate was measured in 20 patients receiving continuous ambulatory peritoneal dialysis (CAPD) and 20 patients receiving hemodialysis (HD). All patients had levels well above the reference range of less than 2.0 to 5.0 mumol/L (less than 0.18 to 0.44 mg/L), the medians being 34 mumol/L (2.99 mg/L) and 42 mumol/L (3.70 mg/L) for the two groups, respectively. Plasma oxalate did not differ significantly in the two groups. Plasma oxalate was not influenced by the number of months patients had received dialysis treatment, but a significant correlation was found between oxalate and creatinine in the 40 patients studied (P less than 0.02, r = 0.38). Predialysis oxalate levels were reduced by approximately 60% following HD, but returned to 80% of the predialysis levels within 24 hours and 95% within 48 hours. Oxalate levels did not differ significantly in samples taken before, during, and after exchanges of CAPD fluid. That the patients treated with CAPD did not have higher oxalate levels than the HD group suggests that the continuous nature of the former treatment compensates for the lower oxalate clearance by the peritoneum. The reported higher risk of oxalosis associated with intermittent peritoneal dialysis has led to a similar risk being postulated for CAPD; however, the present study indicates that if such a risk exists, it cannot be explained by higher levels of oxalate or ionized calcium in these patients.     

Evaluation of valaciclovir dosage reduction in continuous ambulatory peritoneal dialysis patients

In continuous ambulatory peritoneal dialysis (CAPD) patients, acyclovir-induced neurotoxicity is reported to be associated with high serum drug levels even when following the recommended reduced doses for this renal failure population. In view of the high oral bioavailability of valaciclovir (the L-valyl ester of acyclovir) the risk of neurotoxicity becomes more prominent. The present study was conducted in 12 CAPD patients who were administered a single oral dose of 500 mg valaciclovir. Acyclovir was analyzed by high-performance liquid chromatography. Relative pharmacokinetic parameters were estimated based on acyclovir concentrations at 8, 12 and 24 h post-dose. High inter-patient variations were observed with acyclovir apparent total clearance 7.238 +/- 4 l/h and half-life (T1/2) 22.27 +/- 16.82 h. However, dosage simulations confirmed supratherapeutic acyclovir concentrations for all participants when following the recommended dose of 1,000 mg valaciclovir/24 h for varicella zoster infections.     

Single UK centre experience on the treatment of PD peritonitis--antibiotic levels and outcomes.

BACKGROUND: There are few studies of the pharmacokinetics of vancomycin and gentamicin in peritoneal dialysis (PD) patients and the influence of antibiotic concentrations on treatment outcome. Concerns about resistance to ceftazidime and potential of aminoglycoside toxicity make the choice of empiric antibiotic difficult. METHODS: We retrospectively collected data from 613 patients on PD between 1 June 2002 and 31 December 2005. During this time, we adopted a protocol that minimized aminoglycoside exposure to patients with residual renal function and carefully monitored serum antibiotic concentrations. RESULTS: There were no statistical differences in mean day-5 vancomycin concentrations for continuous ambulatory peritoneal dialysis (CAPD) vs automated peritoneal dialysis (APD) and for anuric vs not-anuric patients. However, low levels (<12 mg/l) were recorded for 12.8% CAPD and 15% APD patients. These remained low at day 10 in 16% patients (25% if not anuric) despite incremental dosing. Vancomycin concentration did not predict cure or relapse of Gram-positive or culture-negative peritonitis. Gentamicin concentration (>2 mg/l in >50% patients) did not predict outcome of Gram-negative and culture-negative peritonitis. Moreover, cure rates were the same irrespective of whether gentamicin was continued for 14 days or was switched to ceftazidime after 5 days. CONCLUSION: We have confirmed that the International Society for Peritoneal Dialysis (ISPD) dosing guideline for vancomycin in CAPD and APD patients produces adequate serum concentrations of the antibiotics in the vast majority. However, large incremental dosing of vancomycin is needed if day-5 levels are low; especially for not-anuric patients. Whilst evidence of gentamicin toxicity in PD remains controversial, ISPD dosing regimen resulted in high levels for >50% patients. High gentamicin concentrations did not correlate with treatment success, but switching gentamicin to ceftazidime at day 5 appeared safe and limited aminoglycoside exposure. Increasing vancomycin and gentamicin concentrations do not appear to improve cure rates and alternative strategies (such as combination treatment) should be considered for future research.     

Serum beta 2-microglobulin concentration and its removal in patients treated with continuous ambulatory peritoneal dialysis

This study was performed to clarify serum beta-2 microglobulin (beta 2-M) level and its change in 50 CAPD and 56 HD patients. There was significant correlation between duration of dialysis and serum beta 2-M level in CAPD and HD patients treated under 12 months, but no correlation in those treated over 12 months. Serum beta 2-M level was 33.5 +/- 9.1 mg/l in 45 CAPD patients treated over 12 months, and 46.2 +/- 21.1 mg/l in 35 HD patients. In 26 CAPD patients treated over 12 months, clearance and removal of beta 2-M were 1.0 +/- 0.3 ml/min and 43.0 +/- 17.8 mg/day. There was significant correlation between dwell time and beta 2-M removal (p less than 0.01), and these results suggested beta 2-M was removed by diffusion. Because CAPD treatment can lower serum beta 2-M level compared to HD, there is possibility that CAPD is useful at prevention of dialysis associated amyloidosis.     

Altered aminoglycoside pharmacokinetics in the critically ill

We studied prospectively 49 patients being treated in an intensive care unit with aminoglycosides for gram-negative sepsis. Pharmacokinetic data were calculated from three post-dose serum levels using a one-compartment model. Doses required to achieve peak levels between 5 and 10 mg/l with trough levels approximately 1.0 mg/l ranged between 2 and 12 mg/kg per day (mean dose 7 mg/kg per day). During therapy 60% of the patients had a change in their apparent volume of distribution (Vd) of greater than 20%. These patients were likely to have confirmed infection and to be febrile at the start of treatment. Two to three weeks after discharge ten patients were restudied after a single dose of aminoglycoside. There was a reduction in mean Vd from 0.24 to 0.18 l/kg (P less than 0.02). Critically ill patients have significantly larger volumes of distribution and may require larger doses per kilogram of body weight of aminoglycoside to achieve therapeutic concentrations. Due to considerable variation in kinetic parameters, the use of standard doses or dosing nomograms is not recommended.     

Vitamin A losses during continuous ambulatory peritoneal dialysis

Since continuous ambulatory peritoneal dialysis (CAPD) causes losses of certain plasma proteins and their ligands, we examined the serum concentrations of vitamin A and retinol-binding protein (RBP), as well as the concentrations of vitamin A in the skin and dialysis fluid from 32 patients on CAPD over a period of 1-30 months (mean 7.5). The mean values of vitamin A and RBP in serum were 2-4 times higher than those in the healthy controls; a consistent finding in patients with chronic renal failure. Similarly, the vitamin A concentrations in skin were elevated in the CAPD patients (p less than 0.01). The vitamin A content of the dialysate (mean 1.4 mumol/24 h), which correlated significantly with the serum vitamin A concentration (r = 0.67), was constant during CAPD treatment. RBP was present in the dialysate and its concentration closely correlated with that of vitamin A (r = 0.95), indicating that the transperitoneal diffusion involved retinol-RBP. This conclusion was supported by calculations of clearance rates. Despite the considerable losses of vitamin A in CAPD fluid, the patients' vitamin A concentrations in serum and skin remained elevated. Whether extended CAPD treatment (greater than 30 months) may eventually affect the vitamin A situation in chronic renal failure warrants further observations.     

Lovastatin in glomerulonephritis patients with hyperlipidaemia and heavy proteinuria.

Lovastatin, a 3-hydroxy-3-methylglutaryl coenzyme A inhibitor, was given to 14 patients with unremittent nephrotic syndrome (heavy proteinuria with hyperlipidaemia) for 6 months. Treatment was started at an initial dose of 20 mg/day, increasing to a maximum of 80 mg/day. Treatment was well tolerated except in two patients: one developed rhabdomyolysis and one severe hypertriglyceridaemia requiring an additional antihyperlipidaemic agent. Lovastatin was effective in reducing serum cholesterol, LDL-C and apolipoprotein B in the remaining 12 patients. Cholesterol was reduced by 31% from 8.24 +/- 0.49 mmol/l (mean +/- SEM) to 5.7 +/- 0.18 mmol/l after 6 months (P less than 0.001). LDL-C was normalized to 3.26 +/- 0.21 mmol/l from a pretreatment value of 5.76 +/- 0.48 mmol/l (P less than 0.001), a decrease of 43%. Serum apolipoprotein B was also normalized to 1.11 +/- 0.09 g/l from a basal level of 1.51 +/- 0.10 g/l (P less than 0.05). Triglyceride, HDL-C and apolipoprotein A1 concentrations were unchanged. Proteinuria as well as renal albumin clearance were unchanged. GFR by plasma radioisotope Cr-EDTA clearance for the whole group was unaltered by treatment. However, among those with relatively good pretreatment renal function (GFR greater than 70 ml/min per 1.73 m2), GFR increased at the end of 6 months' treatment (118.2 +/- 15 ml/min per 1.73 m2 versus 77.6 +/- 8.4 ml/min per 1.73 m2 in wash-out phase).(ABSTRACT TRUNCATED AT 250 WORDS)     

Calcium mass transfer in CAPD: the role of convective transport

One hundred and fifty calcium (Ca) balance studies were performedIn 50 patlents treated with CAPD using dialysate with a 1.75mmol/l (7 mg/dl) Ca content, in order to calculate the peritonealbalance of Ca by measuring the Ca in all the effluent for a24-h period, and looking at the influence of serum ionized Caand the ultrafiltration rate in the calcium balance. Of the150 balance studies, 77 were made using four exchanges of dialysateper day and 73 using three exchanges per day. The serum ionizedCa was 1.17±0.09 mmol/l. the ultrafiltration 844±723ml/day and the peritoneal Ca transfer 39±46 m/day. Thenet Ca absortion with four exchanges was less than that withthree exchanges per day. There was a strong negative correlationbetween the peritoneal Ca absortion and the ultrafiltration(r=–0.7, P<0.00001) and with the ionized Ca(r=–0.49,P<0.0001). Thirtythree peritoneal balance studies showeda negative Ca balance and in all 33 cases ultrafiltration wasgreater than 350 ml/day. We conclude that the peritoneal balanceof Ca depends not only on the serum ionized Ca, but also onultrafiltration. The lesser Ca gain observed with four dialysisexchanges per day is due to greater illtrafiltratlon rates presentin thls setting.     

Pharmacokinetics of intermittent intraperitoneal ceftazidime

Ceftazidime is currently recommended as an alternative first-line agent in the treatment of peritonitis and for Pseudomonas peritonitis. The pharmacokinetics of intermittent intraperitoneal (i.p.) ceftazidime have been poorly characterized. This study was designed to characterize the pharmacokinetic disposition of a single dose of ceftazidime in anuric and non-anuric CAPD patients, over 48 hours. This was a prospective, open label, pharmacokinetic study. The study was conducted in an independent, outpatient dialysis center. Ten volunteer continuous ambulatory peritoneal dialysis (CAPD) patients with and without residual renal function, no peritonitis or antibiotics in the previous 4 weeks, and on CAPD for at least 2 months were recruited. Patients received a single dose of i.p. ceftazidime (15 mg/kg) in the first daytime exchange over a 6-hour dwell, after an overnight dwell. Serum, urine, and dialysate were collected over a 48-hour period. A high-pressure liquid chromatography (HPLC) assay was used to analyze ceftazidime in these samples. Pharmacokinetic parameters were calculated. Six of the 10 patients were non-anuric with a mean residual renal creatinine clearance of 2.9 +/- 1.6 mL/min. The mean +/- SD bioavailability was 72% +/- 14%, and the volume of distribution was 0.34 +/- 0.08 L/kg. The mean serum elimination half-life of 22 +/- 5 hours. The peritoneal clearance was 5.74 +/- 1.6 mL/min. No difference was detected between anuric and nonanuric patients. Mean plasma and dialysate concentrations at 24 hours were 24 +/- 6 microg/mL and 18 +/- 7 microg/mL, respectively, and were 12.0 +/- 3.6 microg/mL and 7.4 +/- 3.1 microg/mL at 48 hours, respectively. Once-daily i.p. dosing of ceftazidime achieves serum and dialysate levels greater than the MIC of sensitive organisms over 48 hours.     

Oxalate Metabolism in End-Stage Renal Disease: the Effect of Ascorbic Acid and Pyridoxine

Oxalate metabolism was studied in ten patients with end-stagerenal disease. No patient with primary hyperoxaluria was includedin this study. Five patients were on regular haemodialysis andfive patients were on chronic ambulatory peritoneal dialysis(CAPD). Oxalate metabolism was assessed by measurement of plasmaoxa late concentration (P_ox) oxalate metabolic pool size (OxMP),tissue oxalate accumulation rate (TOxA), oxa late productionrate (OxPR) and dialysis clearance of oxalate (DC_ox These observationswere made on three separate occasions in each of the ten patients:initially when the patients were taking a routine ascorbic acidsup plement of 100mg per day; then after a period of I monthwith no ascorbic acid supplement; and then finally after a furtherperiod of I month's treatment with pyridoxine 800 mg daily. The values for P_ox OxMP and TOxA were significantly increasedin all ten patients and in the range observed in some patientswith type I primary hyperoxaluria. There was no significantdifference between immediate pre haemodialysis P_ox and the P_oxin the CAPD patients. The DC was very much greater during haemodialysis(mean 85 mI/mm) than during CAPD (mean 8 mI/mm). The acute fall,in P during haemodialysis was greater than 50% of the immediatepre-haemodialysis concentration. Ascorbic acid in a dose of 100 mg/day had no signifi cant effecton the parameters of oxalate metabolism studied. Pyridoxinein a dose of 800 mg/day produced a significant fall in P_ox inboth haemodialysis and CAPD patients.     

Cefoperazone in the Treatment of Peritonitis in Continuous Ambulatory Peritoneal Dialysis Patients

Cefoperazone is a third-generation cephalosporin that is active against a broad spectrum of gram-positive and gram-negative bacteria. We added this antibiotic to peritoneal dialysis solution at a concentration of 62.5 mg/L to treat peritonitis in six continuous ambulatory peritoneal dialysis (CAPD) patients. Serum drug concentrations were obtained at 0, 0.5, 1, 2, 4, and 24 h after instituting antibiotic therapy. Rapid uptake by blood of the antibiotic across the peritoneal membrane occurred when the latter was inflamed. Adequate bactericidal serum levels for many bacteria were obtained in less than 4 h. Cefoperazone effectively eradicated peritonitis in all patients.