Health Guide
Drug Guide

Vitamin K

What is it?

Vitamin K is a fat soluble vitamin used in the treatment of vitamin K deficiency caused by broad-spectrum antibiotics (used to treat infection), cephalosporins (used to treat infection), and prednisone (steroid). It is also supplemented in combination with other vitamins when malabsorption (decreased inability to absorb vitamins, mineral, and nutrients from food) is present. vitamin K is given, under the supervision of a doctor, to newborn babies to prevent hemorrhage (bleeding) and to patients on blood thinning medicine whose blood has become too thin. Vitamin K has also been used in the prevention and treatment of osteoporosis (brittle bones). Vitamin K1 (phylloquinone) is found naturally in leafy green vegetables (broccoli, brussel sprouts, cabbage, kale, lettuce, parsley, spinach, turnip greens, and water cress), cauliflower, and the vegetable oils from soybean, cottonseed, canola, and olive. Bacteria present in the human bowel produce vitamin K2.

Other names for vitamin K include: Vitamin K1 or Phylloquinone, Phytonadione, and Phytomenadione; Vitamin K2 or Menatetrenone; Vitamin K3 or Menadione.

Ask your doctor, nurse, or pharmacist if you need more information about this medicine or if any information in this leaflet concerns you.

Before Using:

Tell your doctor if you


Talk with your caregiver about how much vitamin K you should take. The amount depends on the strength of the medicine and the reason you are taking Vitamin K. If you are using this medicine without instructions from your caregiver, follow the directions on the medicine bottle. Do not take more medicine or take it more often than the directions tell you to.

To store this medicine:

Keep all medicine locked up and away from children. Store medicine away from heat and direct light. Do not store your medicine in the bathroom, near the kitchen sink, or in other damp places. Heat or moisture may cause the medicine to break down and not work the way it should work. Throw away medicine that is out of date or that you do not need. Never share your medicine with others.

Drug and Food Interactions:

Do not take vitamin K without talking to your doctor first if you are taking:


Side Effects:

Call your doctor right away if you have any of these side effects:

Other Side Effects:

You may have the following side effects, but this medicine may also cause other side effects. Tell your doctor if you have side effects that you think are caused by this medicine.


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2. Yaguchi M, Miyazawa K, Otawa M et al: Vitamin K2 therapy for a patient with myelodysplastic syndrome. Leukemia 1999; 13(1):144-145.

3. Knapen MHJ, Hamulyak K & Vermeer C: The effect of vitamin K supplementation on circulating osteocalcin (bone Gla protein) and urinary calcium excretion. Ann Intern Med 1989; 111:1001-1005.

4. Iwamoto I, Kosha S, Noguchi S et al: A longitudinal study of the effect of vitamin K2 on bone mineral density in postmenopausal women a comparative study with vitamin D3 and estrogen-progestin therapy. Maturitas 1999; 31(2):161-164.

5. Aisaka K, Uesato T, Miwa et al: Evaluation of vitamin K2 (menatetrenone) administration with hormone replacement therapy on prevention of osteoporosis in climacteric women. Ninth International Menopause Society World Congress on the Menopause, October 1999: 79-83.

6. Feskanich D, Weber P, Willett WC et al: Vitamin K intake and hip fractures in women: a prospective study. Am J Clin Nutr 1999; 69:74-79.

7. Zipursky A: Prevention of vitamin K deficiency bleeding in newborns. Br J Haematol 1999; 104:430-437.

8. Wong DA & Freeman S: Cutaneous allergic reaction to intramuscular vitamin K1. Aust J Dermatol 1999; 40:147-152.

9. Keough GC, English JC & Meffert JJ: Eczematous hypersensitivity from aqueous vitamin K injection. Cutis 1998; 61:81-83.

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17. Product Information: Mephyton(R), phytonadione (vitamin K1). Merck & Co., Inc., Whitehouse Station, NJ, 2004.

18. Karlson B, Leijd B & Hellstrom K: On the influence of vitamin K-rich vegetables and wine on the effectiveness of warfarin treatment. Acta Med Scand 1986; 220:347-350.

19. Kudo T: Warfarin antagonism of NATTO and increase in serum vitamin K by intake of NATTO. Artery 1990; 17:189-201.

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21. Dinnen RD & Ebisuzaki K: The search for novel anticancer agents: a differentiation-based assay and analysis of a folklore product. Anticancer Res 1997; 17:1027-1034.

Last Updated: 9/15/2016

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