Mechanism of urinary excretion of cephaloridine and its effects on renal function in animals

Effects of L-carnitine on the renal tubular transport of cephaloridine

It has been demonstrated recently that cephaloridine (Cld) inhibits the tubular reabsorption of filtered carnitine (Carn) in the rabbit kidney. This interaction has suggested that the limited net cell-to-luminal fluid movement of Cld following its secretory transport across the antiluminal membrane might result from a balance of active Cld reabsorption by a Carn carrier at the brush border approximately equal to its secretion into the tubular fluid, rather than the previously proposed luminal membrane block. Studies were done to determine the effects of L-Carn, 750 mg/kg, i.v. on the tubular secretion and cortical concentrations of Cld, infused i.v. at a dose of 28 mg/kg (Carn:Cld molar ratio = 70:1). The fractional excretions of Cld during three consecutive periods of 10 min each, one before and two following the bolus infusion of Carn, were (means +/- SEM): 1.18 +/- 0.14, 1.20 +/- 0.14, and 1.16 +/- 0.11, respectively (N = 6 each; differences NS). Cortex-to-serum concentration ratios of Cld in control and Carn-treated rabbits were 10.43 +/- 0.32 and 10.16 +/- 0.86, respectively (NS). The data provide evidence against the reabsorptive transport of Cld by a Carn carrier, and do not support a model of balanced secretion and reabsorption as the cause of limited clearance despite significant secretory transport of Cld into the tubular cell.

Effects of KW-3902, a novel adenosine A1-receptor antagonist, on cephaloridine-induced acute renal failure in rats

We investigated the possible renal protective effects of KW-3902 (8-(noradamantan-3-yl)-1,3-dipropylxanthine), a selective and potent adenosine A1-receptor antagonist, against cephaloridine (CER)-induced acute renal failure (ARF) in rats. ARF was induced by intravenous injection of CER at a dose of 600 mg/kg body weight. KW-3902 at doses higher than 0.01 mg/kg (p.o.) dose-dependently attenuated the decrease of creatinine clearance and the increase of proteinuria in rats with CER-induced ARF. In contrast, furosemide and trichlormethiazide (TCM) increased urinary protein and aggravated the serum parameters. These results suggest that KW-3902 has some advantages over furosemide and TCM when used in combination with CER. In the diuretic study in the rats with established ARF induced by CER, KW-3902, furosemide and TCM caused a significant increase in sodium excretion, whereas acetazolamide was ineffective. These results suggest that the proximal tubule is functionally damaged in rats with CER-induced ARF, in accord with the histological observation demonstrating the degeneration of the proximal tubule. From the fact that KW-3902 induces diuretic action even in CER-induced ARF, it is suggested that KW-3902 acts, directly or indirectly, on the proximal tubule or other tubular sites in the kidney, resulting in the diuretic effect.

Protective effect of piperacillin against nephrotoxicity of cephaloridine and gentamicin in animals

The protective effect of piperacillin against the nephrotoxicity of cephaloridine and gentamicin was examined in experimental animals. In rabbits, piperacillin was infused at a dose of 1 mg/kg (body weight) per min over 225 min and cephaloridine (300 mg/kg) was intravenously administered as a bolus 45 min after the start of a drip infusion. Blood urea nitrogen, serum creatinine, and N-acetyl-beta-D-glucosaminidase (NAG) in urine were measured as the renal toxicological parameters before and 24 h after cephaloridine dosing. Although the single administration of cephaloridine significantly elevated these parameters, the elevation was prevented by the concomitant administration of piperacillin. The protective effect of piperacillin was superior to those of cephalothin and fosfomycin. In rats, piperacillin (1,000 mg/kg) was intravenously administered and immediately followed by the intramuscular administration of gentamicin (100 mg/kg) every 24 h for 5 days. When piperacillin was concomitantly administered with gentamicin, the elevations of blood urea nitrogen, serum creatinine, and urinary NAG were significantly lower than when gentamicin was given alone. The concomitant administration of piperacillin resulted in a significant protective effect against the nephrotoxicity of cephaloridine in rabbits and of gentamicin in rats. Histopathological observation also supported the protective effect of piperacillin. The protective mechanism of piperacillin might be the inhibition of transport from the peritubular side to tubular cells for cephaloridine and from both the peritubular and luminal sides for gentamicin.

Prediction of the disposition of beta-lactam antibiotics in humans from pharmacokinetic parameters in animals

Various pharmacokinetic parameters (disposition half-life, total body clearance, renal clearance, hepatic clearance, volume of distribution, intrinsic clearance and volume of distribution of unbound drug) of six beta-lactam antibiotics were compared in mouse, rat, rabbit, dog, monkey, and human. Two methods for prediction of the disposition of the beta-lactam antibiotics in humans by extrapolation of the animal data were evaluated. One was the Adolph-Dedrick approach, which can be used to predict clearances in humans from the relationship between intrinsic clearances and body weight in the other five species. The volume of distribution in humans was predicted from the relationship between the volume of distribution and serum unbound fraction in the five species. The other was the Boxenbaum approach, which can be used to predict the pharmacokinetic parameters of the six beta-lactam antibiotics in humans by using the regression lines of log-log plots of intrinsic clearance and volume of distribution of unbound drug in a single species, in this case the monkey. The half-life calculated according to the latter method had a smaller absolute error than that calculated according to the former method, but the better method for extrapolation of animal data to humans seems to be the former method, which does not require a priori information regarding structure-pharmacokinetic relationships among the antibiotics.

Association of renal injury with combined cephalothin-gentamicin therapy among patients severely ill with malignant disease

There is a high incidence of primary renal tubule damage among patients with malignant disease who die following recent treatment with combinations of cephalothin and gentamicin. Administration of this combination of antibiotics appears to make the patient appreciably more susceptible to severe renal injury if an additional, often minor, insult to the renal tubules is superimposed. In the present study, significant blood loss or bacterial infection not promptly controlled by the antibiotic combination were two factors that provided this additional insult to many patients; the renal injury in these patients could not be attributed to bleeding or infection alone. The combination of cephalothin plus gentamicin carries the potential of causing renal tubule injury and places the patient severely ill with malignant disease at risk for renal failure from many clinical complications which are commonly associated with their primary illness.

Renal handling and lymph concentration of two cephalosporin analogues, cephacetrile and cephaloridine: an experimental study in dogs

Cephacetrile (CIBA 36' 278-Ba) and cephaloridine (both cephalosporin derivatives) were compared in dogs with regard to their possible nephrotoxicity, renal handling, and concentration in the renal lymph. No adverse acute effect of either drug on the glomerular filtration rate and effective renal plasma flow was found at very high concentrations in the plasma, with or without concomitant administration of a potent diuretic (furosemide). Cephaloridine was filtered only by the kidney, whereas there was evidence that cephacetrile was also excreted by tubular secretion at low concentrations. The renal lymph concentration of the two antibiotics (in the hilar as well as the capsular lymph vessels) was found to be significantly lower than the simultaneous arterial plasma concentrations. When concentrations in the plasma were high, the relative lymph concentrations of cephaloridine and cephacetrile were in the same range as those of iothalamate (70 to 90% of the arterial plasma level), whereas at low plasma concentrations the lymph concentration of cephacetrile was markedly lower, a finding possibly explained by the active tubular secretion of cephacetrile.

The nephrotoxicity and histology of cephaloridine and its polymers in rats

Cephaloridine nephrotoxicity for female Sprague-Dawley rats has been confirmed, but can be reduced by administering the drug in dilute rather than concentrated solution. The commercial preparation contains polymers which show varying nephrotoxicity. Mixing the fractions in pairs fails to cause the damage seen after giving the commercial preparation. Mixing the 3 major fractions to reconstitute the commercial preparation only produces about half of the expected damage. If each fraction is given at high dosage, 2·2 g./kg., different degrees of damage result, least with the large polymer, greater with the medium-size polymer, and greatest with the fraction whose molecular weight is less than 1000 and which contains monomers and dimers of cephaloridine, and probably degradation products. The damage is almost comparable with that due to commercial cephaloridine. Pyridine causes minimal nephrotoxicity at equimolar dose levels.

Histology shows proximal tubule cell coagulative necrosis, followed by colliquative necrosis, and repair firstly by flattened, later by cubical then columnar epithelium, finally with a brush border. The groups given smaller doses of the drug or its fractions show a subtle sleeving effect of the brush borders which detach from the underlying cell bodies, individual cell necrosis, and exfoliation or enucleation of cells. Cytoplasmic vacuolation is prominent occasionally. There is no sharp distinction between nephrotoxicity and the normal processes of exfoliation and repair. Granular precipitate and PAS positive homogeneous casts accompany severe damage.

The chemical and histological results suggest that the pathogenic mechanisms responsible for damage to the tubules may be (a) precipitation of drug (or its fractions) from concentrated solution, (b) polymerization, which may be more likely to cause damage of the brush borders than precipitation since polymer is less able to redissolve than pure drug. These processes could be aggravated by other nephrotoxic agents (including diuretics), pH of tubular contents, anatomical differences between proximal convoluted tubules of the 2 sexes, and a vascular component which from histological observation does not clearly implicate renin.

Enhancement by potent diuretics of renal tubular necrosis induced by cephaloridine

1. Administration of frusemide or ethacrynic acid to cephaloridine-treated mice increased both the incidence and extent of proximal renal tubular necrosis compared with that obtained in cephaloridine-treated control mice.2. Administration of frusemide to cephaloridine-treated rats produced significant changes in urine output, electrolyte excretion and proteinuria, and plasma urea nitrogen and creatinine values were significantly increased compared with controls or rats that received frusemide or cephaloridine alone.3. Histological examination of the kidneys showed a higher incidence and greater extent of tubular necrosis in rats that received both frusemide and cephaloridine.4. It is suggested that this adverse drug interaction may have contributed to the deterioration in renal function observed in some patients treated with diuretics and cephaloridine concurrently.