Vitamin B12 is virtually nontoxic in humans, even if given in doses of 10,000 to 20,000 times the RDA (recommended daily allowance) given orally or intramuscularly. People who are injected intramuscularly with large doses of vitamin B12, 10, 000 micrograms or more, often report an immediate feeling of warmth, energy, and general glow of health. This feeling is short, often a few seconds of duration; it is transitory and usually is more frequent and pronounced on the first injection.
If vitamin B 12 is injected intravenously, the patient may develop a skin rash, mild, not itchy, and more pronounced in the trunk and face. This rash usually clears up in three to four days.
Large doses of vitamin B 12 given orally or intramuscularly may exacerbate preexisting acne. Very few cases have been reported.
In two previous works, one done by the British author G. Houding in 1968 and another by the Italian Physician C. Nava in 1971, both reviewing many years of medical literature, reported that only minor vitamin b 12 shots side effects occur with the administration of vitamin B 12.
The vitamin B 12 shots manufacturers, like all companies, advises one to be aware of these very rarely seen adverse side effects of vitamin B 12: pruritus, urticaria, erythema, acne, red urine due to cobalt, pulmonary edema and congestive heart failure, polycythemia vera, mild diarrhea, and a feeling of swelling of the entire body. These very uncommonly seen adverse reactions are only seen in the first days of therapy. But all these are considered as the potential side B 12 shots side effects.
There is much confusion and misunderstanding about vitamin B 12, its metabolism, benefits and undesirable effects. Much more research is needed to clarify and understand vitamin B 12. the current medical studies challenge past points of view that vitamin B 12 must only be prescribed to patients who show b12 deficiency of this vitamin confirmed by routine blood tests.
Vitamin B 12 is not a miracle drug, not a remedy to cure or soothe each malady, not a snake oil, as it has been called by many practitioners, but a drug with wonderful properties, some of them known to us, some others not yet recognized. More studies and more research are needed. It has been written that without vitamin B 12, one can lose his mind.
Vitamin B12 in large doses, given intramuscularly, was used specially in these main areas: treatment of lower back pain and sciatica, prevention of memory loss in the elderly, and treatment of trigemina neuralgia.
Sciatica and lower back pain- every patient with sciatica or lower back pain, except the patients under compensation for work accidents, were given a trial of large doses of vitamin B 12, usually 1, 000 to 2, 000 micrograms, injectable intramuscularly, every three days for at least four to five weeks followed by oral vitamin B 12 in tablet form, 1, 000 micrograms daily, or three months further. After recovery, they received 100 micrograms daily orally.