Final answer:
Vitamin K is an antagonist of the drug warfarin, as it promotes blood clotting which counteracts the anticoagulant effects of warfarin. Vitamin C is a water-soluble vitamin, and pharmacogenomics may help in warfarin dosing by considering individual genetic differences.
Step-by-step explanation:
The vitamin that is an antagonist of the drug warfarin (Coumadin) is vitamin K. Vitamin K is involved in the process of blood clotting and can counteract the effects of warfarin, which is an anticoagulant used to prevent blood clots. In patients who take warfarin, intake of vitamin K needs to be monitored to ensure the effectiveness of the drug.
Regarding the water-soluble vitamins, it is important to note the B-complex vitamins and vitamin C are water-soluble. The B-complex group includes several vitamins such as Thiamine (B1), Riboflavin (B2), Niacin (B3), and many others. Vitamin C, also known as ascorbic acid, is likewise water-soluble and is essential for numerous bodily functions including immune support.
Pharmacogenomics could be utilized to assist patients by providing insight into how individual genetic variations affect the liver's ability to metabolize warfarin. This could lead to more personalized dosing and a lowered risk of overdose.