Folate & B12 / Forms
Forms of folate and vitamin B12
FOLATE
- FOLIC ACID is the synthetic (more stable) form of folate used in supplements
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available in oral formulation, but can also be given IM, IV or SC if GI absorption is impaired
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- LEUCOVORIN (5-formyl-TH4, folinic acid) is a naturally ocurring compound that is used to replace folate in rescue therapy
- LEUCOVORIN doesn't require dihydrofolate reductase for conversion to tetrahydrofolate (i.e., its use can't be blocked by antifolates)
VITAMIN B12
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Naturally occurring forms: adenosylcobalamin, methylcobalamin
- Medicinal forms are given IM, IV, transdermal (patch), spray (rarely orally; see discussion of vitamin B12 deficiency):
- HYDROXOCOBALAMIN:
- used for treatment of cyanide poisoning
- more plasma protein bound, therefore remains in circulation longer
- CYANOCOBALAMIN
- HYDROXOCOBALAMIN: