vitamin-k-semiquinone-radical and flomoxef

Antibiotics of the beta-lactam class may cause coagulation defects and bleeding. It has been suggested that N-methyltetrazolethiol (NMTT), a common side chain group at the 3'-position of the cephem or 1-oxacephem frame, could be responsible for the hypoprothrombinemic effect of the antibiotics and that it could inhibit the liver vitamin K-epoxide reductase activity. Flomoxef (6315-S) is a new oxacephem antibiotic which differs from latamoxef because it has [1-(2-hydroxethyl)-1H-tetrazol-5-yl] thiomethyl (HTT) as a side chain at the 3'-position of cephem group instead of NMTT and an extensive modification of 7 beta-acylamino side chain. The present study was carried out to study its effects on vitamin K-dependent blood coagulation parameters in human volunteers. Ten adult patients (6 men and 4 women), suffering from chronic bronchitis, entered into the study. Each patient received ten 1 g i.m. injections of flomoxef at 12-hourly intervals. Apparently, the treatment with this oxacephem antibiotic had no significant effect. PT, PTT and fibrinogen remained in the normal range in all patients and factors II+VII+X, protein C, protein S and AT III were not depleted. The trend was similar both in men and women. Based on the results of the present study, we conclude that flomoxef is an antibiotic that does not exhibit an effect on blood coagulation, even in males.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Aged; Blood Coagulation Disorders; Blood Coagulation Factors; Blood Coagulation Tests; Bronchitis; Cephalosporins; Chronic Disease; Female; Humans; Lung Diseases, Obstructive; Male; Middle Aged; Protein C; Protein S; Vitamin K

The effect of flomoxef, a newly developed oxacephem antibiotic with an N-hydroxyethyltetrazolethiol (HTT) side chain, on blood coagulation and alcohol metabolism was compared with that of a series of cephalosporin antibiotics with N-methyltetrazolethiol (NMTT), thiadiazolethiol (TDT) or methylthiadiazolethiol (MTDT) side chains in position 3' of the cephalosporin nucleus known to cause hypoprothrombinemia and bleeding in patients who are malnourished, debilitated and/or of high age. A disulfiram-like effect caused by inhibition of aldehyde dehydrogenase was observed for NMTT-containing antibiotics. Studies were carried out on healthy volunteers and on rats. Eight-day treatment with 2 g flomoxef i.v. once or twice daily in five and six healthy male volunteers, respectively, did not cause any significant changes in prothrombin time (PT), coagulation factors II, VII, IX or X, in hepaplastin values or fibrinogen levels, activated partial thromboplastin time (APTT), platelet counts, bleeding time, or collagen- and ADP-induced platelet aggregation. Inhibition of vitamin K epoxide reductase was observed in rats treated with flomoxef, yet to a much lesser extent than observed for cephalosporins with NMTT, TDT or MTDT side chains. This defect was quickly normalized by vitamin K injection. There were no differences between oxacephem (1-O) and cephem (1-S) compounds with respect to effects on blood clotting and platelet aggregation. Flomoxef and its side chain HTT showed no influence on alcohol metbolism.

Topics: Animals; Blood Coagulation; Cephalosporins; Ethanol; Humans; Male; Rats; Structure-Activity Relationship; Vitamin K

Oxacephem antibiotics have been developed to increase the antibacterial activity of cephem antibiotics, but the effect of 1-oxygen replacement of cephem antibiotics on blood coagulation activities is not yet known. Therefore, latamoxef (LMOX), flomoxef (FMOX) and their 1-S congeners were examined for their effects on prothrombin time, activated partial thromboplastin time, plasma prothrombin and Factor VII levels, plasma and liver descarboxyprothrombin (PIVKA-II) levels, and liver microsomal vitamin K epoxide reductase activities in rats kept on a vitamin K-deficient diet. Under the vitamin-deficient states, LMOX, FMOX and their 1-S congeners inhibited the vitamin K epoxide reductase, although the effect of FMOX or its congener was much less than that of LMOX, and they decreased the blood clotting activities in rats fed a vitamin K-deficient diet. However, no difference was found in these effects between LMOX and its 1-S congener or between FMOX and its 1-S congener. This result suggests that the 1-oxygen replacement of cephem antibiotics is not responsible for the hypoprothrombinemic effect of the antibiotics.

Topics: Animals; Blood Coagulation; Cephalosporins; Factor VII; Fibrinogen; Male; Moxalactam; Partial Thromboplastin Time; Platelet Aggregation; Prothrombin Time; Rats; Rats, Inbred Strains; Vitamin K; Vitamin K Deficiency