Dietary deficiency of phylloquinone and reduced serum levels in febrile neutropenic cancer patients.

: In 34 cancer patients with 40 neutropenic febrile episodes requiring broad-spectrum antimicrobial therapy, detailed dietary assessments revealed that deficient and severely deficient phylloquinone intakes (less than or equal to 70 and less than or equal to 25 micrograms/d) were identified during 88% and 38% of all days recorded, respectively. Serum phylloquinone levels and serial prothrombin times (PT) drawn in a similar group of 32 patients revealed that an elevated PT (greater than or equal to 2 s beyond control) was significantly associated (p less than 0.01) with a serum phylloquinone level of less than 4.4 nmol/L. Patients on antimicrobial regimens that suppressed menaquinone-producing intestinal microflora and that contained an N-methylthiotetrazole (NMTT) moiety had an elevated PT significantly more often than did patients receiving antimicrobial agents that preserved the microflora and contained no NMTT moiety (3 of 10 vs 10 of 11, respectively; p = 0.02 Fisher's exact). These data suggest that these patients have a profound deficiency of oral vitamin K intake that may be further augmented by antimicrobial therapy.