Side Effects & Warnings
Caution should be used in patients undergoing angioplasty since an intravenous loading
dose of folic acid, vitamin B6, and vitamin B-12 followed by oral administration taken
daily after coronary stenting might actually increase restenosis rates. Due to the
potential for harm, this combination of vitamins should not be recommended for patients
receiving coronary stents.
Itching, rash, transitory exanthema, and urticaria have been reported. Vitamin B-12 and
pyridoxine has been associated with cases of rosacea fulminans, characterized by intense
erythema with nodules, papules, and pustules. Symptoms may persist for up to four months
after the supplement is stopped, and may require treatment with systemic corticosteroids
and topical therapy.
Diarrhea has been reported.
Peripheral vascular thrombosis has been reported. Treatment of vitamin B-12 deficiency can
unmask polycythemia vera, which is characterized by an increase in blood volume and the
number of red blood cells. The correction of megaloblastic anemia with vitamin B-12 can
result in fatal hypokalemia and gout in susceptible individuals, and it can obscure folate
deficiency in megaloblastic anemia. Caution is warranted.
Vitamin B-12 is contraindicated in early Leber's disease, which is hereditary optic nerve
atrophy. Vitamin B-12 can cause severe and swift optic atrophy.