[Studies on administration of cephalothin sodium after open heart surgery (author's transl)]

Critical cardiac contamination may occur during extracorporeal circulation in open heart surgery. Prophylactic administration of cephalothin sodium (CET) was studied for their safe and adequate serum concentration after open heart surgery in infants and adults. Methods of administration of CET were discussed for infants and adults.

Clinical pharmacology of cefamandole as compared with cephalothin

We compared the pharmacology of cefamandole and cephalothin in six healthy adult male volunteers. After a 1-g, 20-min intravenous (i.v.) infusion, the average peak blood level of cefamandole was 87.6 versus 64.1 mug/ml for cephalothin. An i.v. infusion of 500 mg/h for 2 h (after a loading dose of 750 mg) gave an average steady-state blood level of 28.5 mug/ml for cefamandole and 18.2 mug/ml for cephalothin. Mean peak serum levels after 1 g intramuscularly were similar for the two antibiotics (about 21 mug/ml), but with cefamandole they persisted longer, and the area under the blood level curve was about 25% greater. The average t((1/2)) as determined from both i.v. studies was 34 min for cefamandole versus 30 min for cephalothin. The mean serum clearance for cephalothin, due to its partial conversion to a metabolite, was much greater than for cefamandole (425 versus 272 ml/min per 1.73 m(2)), but the renal clearances were similar for the two antibiotics (268 versus 257 ml/min per 1.73 m(2)). Other values for cefamandole and cephalothin were: 24-h urinary excretion, 80 and 66%; serum protein binding, 74 and 70%; and apparent volume of distribution, 12.8 and 18.5 liters/1.73 m(2), respectively. Thus, the pharmacology of the two antibiotics was similar. Blood levels were somewhat higher with cefamandole i.v., but the results suggest that dosage regimens should be the same for the two antibiotics.

Concentration of antibiotics in renal interstitial fluid: an experimental model

In a new canine experimental model the time concentration relationship of cephalothin in serum, urine, soft tissue interstitial fluid (STIF) and renal interstitial fluid (RIF) were compared simultaneously. Antibiotic concentration in RIF was less than urinary levels but exceeded the serum concentration. Urinary antibiotic concentration does not necessarily reflect concentration in the renal interstitium. This model helps to understand the basic pharmacokinetics of antibiotics in the renal interstitium where pyelonephritis occurs.

Serum levels and urinary excretion of parent antibiotics and desacetyl forms after parenteral administration of cephalothin and cephapirin

When the antibacterial substances of cephalothin and cephapirin in the serum and urine after intramuscular injection were separated and assayed, desacetyl metabolities of both drugs were detected. These tendencies were especially apparent in the tissue concentrations. When both the drugs were given intravenously to healthy volunteers, the amounts of their desacetyl metabolites were not greater in man than in rats.

Comparison of absorption and excretion of cefazolin with cephalothin and cephapirin

Since the discovery of cephalothin in 1962, many semi-synthetic cephalosporins have appeared. To choose the most suitable drug for the clinical treatment of infections, the characteristics of these antibiotics must be sufficiently understood. When cephalosporins which are or will be commercially available are divided into two categories, one consists of cephaloridine, cefazolin and cephalexin which are comparatively stable in the living body; and the other cephalothin, cephaloglycin, cephapirin and cephacetrile which are metabolized into desacetyl compounds with low antibacterial activity. In this study, the author compared the absorption, excretion and some other properties of cefazolin and cephalothin, (widely used clinically), and cephapirin (still under study in Japan).

Paper chromatographic techniques for the determination of cephalothin and desacetylcephalothin in body fluids

Paper chromatographic procedures may be used to detect cephalothin and its metabolite desacetylcephalothin in urine, plasma, synovial fluid, and cerebrospinal fluid. Protein-bound antibiotics are released from plasma, cerebrospinal fluid, and synovial fluid by dilution with an equal volume of dimethylformamide. Data are presented on the sample preparation, paper chromatographic system, and other specific techniques.

Measurement of three antibiotics (penicillin, cephalothin, and chloramphenicol) when present together in mixtures

Benzylpenicillin, cephalothin, and chloramphenicol were measured individually and quantitatively when present together in mixtures at concentrations found in patients. The assay depended on the selective inactivation of two of the antibiotics, permitting the third to be assayed as if present alone. Agar seeded with a chloramphenicol-resistant, penicillinase-negative Staphylococcus aureus was used for a cylinder-plate assay of appropriately diluted fluid to determine the activity of either benzylpenicillin or cephalothin after either beta-lactamase inactivation of the former or ultraviolet light inactivation of the latter. Chloramphenicol was assayed with Sarcina lutea after appropriate beta-lactamase inactivation of both cephalothin and benzylpenicillin. Fluids containing various amounts of the three antibiotics were assayed by this method with less than 8% error. Procedures that fail to measure each antibiotic individually may give larger errors.

Excretion of cephaloridine and cephalothin in patients with renal impairment

Cephaloridine has been shown to possess certain favorable pharmacologic features while retaining the desirable antimicrobial properties of the parent compound, cephalothin. The major advantage of cephaloridine is its relatively greater resistance to metabolic degradation, presumably by the liver. This results in more prolonged blood levels in healthy subjects and a longer half-life in patients with severe renal disease. These features, together with reported enhanced antimicrobial activity and lack of inhibition by serum, suggest that it may replace or substitute for the parent compound, cephalothin, provided further clinical trials indicate that it proves to be an effective agent. Suggestions are given for a modified dosage schedule in uremic patients and during hemodialysis.