To the Editor: A warning needs to be given to pediatricians and obstetricians about using unduly large doses of any water-soluble vitamin K preparation in premature infants. Communications (appearing in Letters to the Editor, Lancet1:669 [March 26]; 819 [April 16] 1955) report fatal hemolytic anemia occurring in two small series of infants. The vitamin K was given in one or more doses of 10 mg. to these premature infants. No evidence of blood-group incompatibility or Rh-factor problem was found.
A further report appeared (Letters to the Editor, Lancet1:819 [April 16] 1955) in substantiation of the hemolytic effect of very large doses (100 mg/kg.) of water-soluble vitamin K given to rats. This hemolysis occurred only in rats deprived of vitamin E. It is known (Rose. C. S., and György, P.: Blood5:1062 [Nov.] 1950) that vitamin E deficiency in rats leads to abnormaly great hemolytic tendency.