1-n-methyl-5-thiotetrazole and Blood-Coagulation-Disorders

The mechanism of hypoprothrombinemia induced by cephalosporins containing the N-methylthiotetrazole (NMTT) side chain has been investigated in a randomized clinical, trial (pilot study) with 14 hospitalized patients (main inclusion criteria: age greater than or equal to 50 years, urinary tract infection, normal prothrombin time. Therapy groups: latamoxef (n = 5), cefoperazone (n = 5), cefotaxime (control, n = 4). Duration of treatment: 7 days). Two patients under cefoperazone exhibited a significant increase of prothrombin time, accompanied by the appearance of PIVKA II (prothrombin induced in vitamin K absence). Both cefoperazone (in 4 patients) and latamoxef (in 3 patients) caused the appearance of endogenous vitamin K1 2,3-epoxide, whereas cefotaxime did not. This confirms the hypothesis that NMTT-cephalosporins are inhibitors of hepatic vitamin K epoxide reductase, and that this is at least partly responsible for the clinically observed hypoprothrombinemia. In older patients treated with these antibiotics, prothrombin time should be controlled before as well as under therapy. Unexpectedly, the patients displaying an appearance of vitamin K1 2,3-epoxide showed a statistically significant increase of endogenous plasma vitamin K levels. This effect needs further investigation.

Topics: Aged; Aged, 80 and over; Azoles; Blood Coagulation Disorders; Cefoperazone; Cefotaxime; Cephalosporins; Female; Humans; Male; Moxalactam; Pilot Projects; Protein C; Prothrombin Time; Random Allocation; Tetrazoles; Urinary Tract Infections; Vitamin K Deficiency

The pharmacokinetics of latamoxef and CPW 86-363, a novel carboxy-pyrazol-cephalosporin, were evaluated in healthy volunteers after intravenous bolus injection of 1 g. Based on concentration-time courses in serum both cephalosporins showed similar distribution properties, although CPW 86-363 was eliminated significantly faster. The route of elimination of latamoxef was mainly via the urine, whereas CPW 86-363 was also excreted into the bile. N-methylthiotetrazole, which is the common side chain in position 3 of both cephalosporins, was found in the serum as well as in the urine. Its rate and extent of formation was higher for latamoxef than for CPW 86-363 and depends rather on the instability of the parent compound than on metabolic transformation. This is supported by studies on the in vitro degradation of both derivatives. The relevance of these findings are discussed in view of secondary coagulopathies, which are associated with cephalosporins having a N-methylthiotetrazole side chain.

Topics: Adult; Azoles; Biotransformation; Blood Coagulation Disorders; Cephalosporins; Humans; Kinetics; Male; Moxalactam; Structure-Activity Relationship; Tetrazoles