PT  - JOURNAL ARTICLE
AU  - I J Mackie
AU  - K Walshe
AU  - H Cohen
AU  - P McCarthy
AU  - M Shearer
AU  - S D Scott
AU  - S J Karran
AU  - S J Machin
TI  - Effects of N-methyl-thiotetrazole cephalosporin on haemostasis in patients with reduced serum vitamin K1 concentrations.
AID  - 10.1136/jcp.39.11.1245
DP  - 1986 Nov 01
TA  - Journal of Clinical Pathology
PG  - 1245--1249
VI  - 39
IP  - 11
4099  - http://jcp.bmj.com/content/39/11/1245.short
4100  - http://jcp.bmj.com/content/39/11/1245.full
SO  - J Clin Pathol1986 Nov 01; 39
AB  - Two patients with low random serum vitamin K1 concentrations but with normal prothrombin times and normal biological assays of the vitamin K dependent coagulation proteins were treated with an N-methyl-thiotetrazole cephalosporin (cefotetan) postoperatively. Four to six days later both patients developed a prolonged prothrombin time and a noticeable and specific lowering of the clotting activities of factors II, VII, IX and X, though the serum vitamin K1 concentrations remained unchanged. Crossed immunoelectrophoresis of prothrombin showed the appearance of a second peak corresponding to descarboxyprothrombin (PIVKA II). These abnormalities corrected after vitamin K administration. These data are consistent with the hypothesis that cephalosporins with an N-methyl-thiotetrazole side chain inhibit the hepatic utilisation of vitamin K but that this only causes hypoprothrombinaemia when liver reserves of vitamin K are low.