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warnings
WARNINGS Patients who have early Leber’s disease (hereditary optic nerve atrophy) have been found to suffer severe and swift optic atrophy when treated with vitamin B 12 . Fatal hypokalemia may occur when severe megaloblastic anemia is treated intensively with vitamin B 12 , as a result of increased erythrocyte potassium requirements (see PRECAUTIONS, Laboratory Tests ). Anaphylactic shock and death have been reported after parenteral vitamin B 12 administration. An intradermal test dose is recommended before cyanocobalamin is administered to patients suspected of being sensitive to this drug. This product contains benzyl alcohol. Benzyl alcohol has been reported to be associated with a fatal "Gasping Syndrome" in premature infants.
ADVERSE REACTIONS No serious toxic reactions have been reported following the intramuscular administration of cyanocobalamin. The following allergic-type reactions have been reported rarely; the relationship of these reactions to cyanocobalamin or other components in the preparation is unknown. Generalized —anaphylactic shock and death have been reported with administration of parenteral vitamin B 12 (see WARNINGS ) Cardiovascular —pulmonary edema and congestive heart failure early in treatment, peripheral vascular thrombosis Hematologic —polycythemia vera Gastrointestinal —mild transient diarrhea Dermatologic —itching, transitory exanthema, urticaria Miscellaneous —feeling of swelling of entire body