Folic acid, also known as vitamin B-9, is an important water-soluble vitamin found in green leafy vegetables and fortified foods. Phenytoin is a medicine given for the management and prevention of seizure disorders. It is important to consult with a physician regarding dietary intake, medications and other health-related conditions.
Use
Folic acid is needed to synthesize, repair and regulate DNA expression, which tells the cells how and when to make proteins involved in the structure and function of cells. It is particularly important during cell division, and cells such as red blood cells with a rapid rate of synthesis require more folate than slower dividing cells. Higher levels are needed during some types of anemia, pregnancy and with certain medications, such as phenytoin.
Phenytoin is one of many drugs used to stop seizures. It is also used to prevent seizures, particularly in people who have a seizure disorder from head trauma or neurosurgery. (See Reference 1, 2 and 3)
Mechanism
Folic acid helps cell enzymes transfer small chemical units called methyl groups. It helps to synthesize, repair and regulate DNA. It also helps synthesize RNA, which is made from DNA and is used as a template for creating protein. A deficiency of folate causes anemia, or low red blood cell counts, by interfering with DNA synthesis and thus, cell division. A deficiency can also lead to defective nerve development, called neural tube defects, in the developing fetus.
In contrast to folate, the mechanism of action of phenytoin is not known. It is believed to block channels in nerve cells that allow sodium into cells, causing them to fire repetitvely, leading to seizures. Therefore, it calms down nerve firing in the brain to stop seizures.
Interactions
Phenytoin can decrease the absorption of folic acid. Some physicians recommend giving people on phenytoin doses of folic acid as well as vitamin B-12 to avoid deficiency and avoid anemia. This depends on the individual situation though, because folic acid supplementation can also lower the blood level of phenytoin and increase the risk of seizures in some people. Therefore, it is important to discuss this with your health-care provider.
Side Effects
As discussed, high levels of either folic acid or phenytoin in a person taking both can lower the blood level of the other. This leads to either anemia in the case of folic acid, or seizures in the case of low phenytoin. In addition, high levels of folic acid are associated with the development of some cancers. Phenytoin can also cause side-effects in some people, such as fetal abnormalities, enlarged gums, sedation, increased risk of suicide and an increased risk of lupus, a disease in which the immune system attacks the body.
References
- "Basic and Clinical Pharmacology"; Bertram Katzung, et al.; 11th Ed 2009
- "Harrison's Principles of Internal Medicine"; Anthony S Fauci, et al.; 17th Ed 2008
- "Robbins and Cotran Pathologic Basis of Disease"; Vinay Kumar, et al.; 8th Ed 2009
Member Comments