warfarin and Ascorbic-Acid-Deficiency

A 64-year-old woman presented with a hemorrhagic perifollicular rash on her legs while taking warfarin. After biopsy, vitamin C deficiency was suggested as the diagnosis, which ascorbic acid assays later confirmed. Clinical resolution of the rash followed supplementation with vitamin C. Patients on a vitamin K limited diet may also be limiting their intake of vitamin C. Physicians should be aware of this possible correlation, and consider checking vitamin C levels in patients with a perifollicular hemorrhagic rash or other signs of vitamin C deficiency while on warfarin.

Topics: Anticoagulants; Ascorbic Acid; Ascorbic Acid Deficiency; Drug Eruptions; Female; Humans; Leg Dermatoses; Middle Aged; Skin Diseases, Vascular; Warfarin

beta- Hydroxyaspartic acid is a rare amino acid, present in all vitamin K-dependent plasma proteins except prothrombin, and is formed by a post-translational hydroxylation of aspartic acid. We have now investigated whether this hydroxylation, like that of proline in collagen, is vitamin C-dependent. The vitamin K-dependent plasma proteins were isolated from normal and scorbutic guinea pig plasma by barium citrate adsorption and the beta- hydroxyaspartic acid content was determined. Compared with normal animals, scorbutic animals showed no significant reduction of beta- hydroxyaspartic acid content. In warfarin-treated animals there was a decreased content of both beta- hydroxyaspartic acid and gamma-carboxyglutamic acid in the barium citrate adsorbed fraction. It was concluded that the post-translational hydroxylation of aspartic acid is unlikely to be vitamin C-dependent.

Topics: 1-Carboxyglutamic Acid; Animals; Ascorbic Acid; Ascorbic Acid Deficiency; Aspartic Acid; Blood Coagulation; Blood Proteins; Guinea Pigs; Hydroxylation; Protein Processing, Post-Translational; Vitamin K; Warfarin

Topics: Animals; Ascorbic Acid; Ascorbic Acid Deficiency; Drug Interactions; Guinea Pigs; Warfarin