From the Guidelines
Vitamin B12 injections are not known to cause leukopenia (low white blood cell count) and are actually essential for proper blood cell formation, including white blood cells. When considering the potential effects of vitamin B12 injections on white blood cell count, it's crucial to understand the role of vitamin B12 in the body. Vitamin B12 plays a significant role in DNA synthesis and cell division, which are essential for the production of blood cells, including white blood cells 1. A deficiency in vitamin B12 can lead to various blood cell formation issues, including leukopenia.
The provided evidence does not directly link vitamin B12 injections with leukopenia. Instead, it highlights the importance of vitamin B12 in preventing stroke by lowering homocysteine levels 1. The study from 2022 published in Stroke suggests that B vitamins, including vitamin B12, can reduce the risk of ischemic stroke by 43% 1. This indicates that vitamin B12 supplementation, when needed, is beneficial and does not cause leukopenia.
In clinical practice, the administration of vitamin B12 injections (typically cyanocobalamin or hydroxocobalamin, given as 1000 mcg doses) is aimed at correcting deficiencies and improving blood cell production. While rare allergic reactions to components in the injection could theoretically affect blood counts, there is no substantial evidence to suggest that vitamin B12 injections cause leukopenia.
If patients receiving B12 injections experience unusual symptoms like frequent infections, fever, or fatigue, they should consult their healthcare provider promptly. The provider may recommend blood tests to check the white blood cell count. However, based on the current understanding and evidence, vitamin B12 injections are not associated with causing leukopenia and are an important part of treating vitamin B12 deficiency 1.
From the Research
Vitamin B12 Injections and Leukopenia
- There is no direct evidence in the provided studies that vitamin B12 injections cause leukopenia (low white blood cell count) 2, 3, 4, 5, 6.
- However, it is noted that vitamin B12 deficiency can cause pancytopenia, which is a reduction in the number of red and white blood cells, as well as platelets 4.
- Vitamin B12 deficiency can also cause dysplastic changes in the bone marrow, which can be misleading and may be mistaken for myelodysplastic syndromes or acute leukemia 4.
- Treatment with vitamin B12 injections can improve pancytopenia and blastic changes in patients with vitamin B12 deficiency 4.
- High doses of vitamin B12 can cause toxicity, but the symptoms are typically unrelated to leukopenia, and include acne, palpitations, anxiety, and insomnia 5.
Mechanism of Vitamin B12 and Hematopoiesis
- Vitamin B12 plays a role in hematopoiesis, and its deficiency can affect the production of red and white blood cells 2, 4.
- The relationship between vitamin B12 and hematopoiesis is complex, and involves the regulation of granulocyte production and metabolism 2.
- Recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) can stimulate hematopoiesis and increase white blood cell counts in patients with bone marrow failure or malignancy 3.