Can pernicious anemia be treated with vitamin B12 pills instead of injections?
Ask the doctor
Q. I have pernicious anemia. I get a monthly injection of vitamin B12. I have heard that there may be a pill that I could take instead. Is that true?
A. Pernicious anemia is a condition that happens when the body doesn't make enough red blood cells because the intestine cannot absorb enough vitamin B12. To be absorbed, the vitamin needs to be attached to a protein called intrinsic factor. It's made by stomach cells.
Pernicious anemia happens when people develop an autoimmune condition that reduces the production of intrinsic factor. Without intrinsic factor, B12 absorption suffers.
The liver normally stores up large amounts of B12. So, it may take several years for the anemia to develop after absorption of the vitamin has stopped. Anemia may cause weakness, fatigue, dizziness, and a rapid heartbeat. B12 deficiency can also result in neurological problems.
Doctors have traditionally given injections of B12 to patients with pernicious anemia. Patients have been "tanked up" with daily injections, followed by weekly and then periodic ones that may continue the rest of their lives.
It turns out, though, that the injections may not always be necessary. Some people with pernicious anemia can get enough B12 into their systems by taking doses of 1 to 2 milligrams in pill form. That may not seem like much, but it's about 500 to 800 times more than the recommended daily intake of 2.4 micrograms. The large amount doesn't pose a danger because people with pernicious anemia absorb only a small fraction of it.
If you go the pill route, it's very important to take the pill every day. If you're forgetful, or circumstances make it hard for you to stick with it, the injections may be the better way to go. Vitamin B12 is also available in the form of pills that dissolve under the tongue, and as a nasal spray and nasal gel.
If you and your doctor decide to try vitamin B12 pills, in whatever form, it will be important to have regular blood tests to be sure you're getting enough of the vitamin.
Image: © Christoph Burgstedt/Science Photo Library/Getty Images/Getty Images
About the Author
Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing; Editorial Advisory Board Member, Harvard Health Publishing
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