I am not a lawyer, but I have been practicing medicine for nearly twenty years, and I am qualified to answer your questions.
Varicose vein disease is a condition in which a blood vessel near the base of the spine becomes narrowed, resulting in the gradual narrowing of the blood vessels in the legs. The narrowing may not be seen until the disease is advanced. The narrowed blood vessels can then block blood flow from other vital organs. This can result in death or severe leg pain. This condition is caused by a deficiency in the vitamin B12. Vitamin B12 is a member of the group of vitamins known as folate. The body can produce it as a by-product of methylation of certain carbohydrates and the metabolism of proteins. People who are not getting enough folate are at higher risk for developing these problems. For more information on the problem, see the Folate Deficiency article. If you are on a high dose of oral antibiotics, your body has developed antibodies to them, which are used to fight infections. These antibodies may be blocking the body's ability to absorb the vitamins in those drugs. Vitamin B12 is used in your body by the kidneys.