Indications for: NASCOBAL
Maintenance treatment in patients with pernicious anemia who are in remission after intramuscular Vit. B12 therapy and who have no nervous system involvement. Treatment of dietary, drug-induced, or malabsorption-related Vit. B12 deficiency not due to pernicious anemia. Prevention of Vit. B12 deficiency in patients with Vit. B12 requirements in excess of normal.
Give at least 1hr before or after hot foods or liquids. Initially 1 spray (500mcg) in one nostril once weekly. Monitor response; may increase dose if serum B12 levels decline after 1 month. If levels persistently low, consider alternative formulations. Defer dose if nasal congestion, allergic rhinitis, or upper respiratory infections occur.
Obtain hematocrit, reticulocyte count, Vit. B12, folate, and iron levels prior to initiation. May need supplemental folate or iron. Monitor B12 blood levels and peripheral blood count 1 month after initiation, 1 month after each dose adjustment, and regularly at 3–6 month intervals. Do not use for Schilling Test. Leber's optic atrophy: not recommended; consider alternatives. Suspected cyanocobalamin hypersensitivity: consider intradermal test dose of parenteral Vit. B12 prior to initiation. May mask previously unrecognized folate deficiency. Risk of hypokalemia and sudden death in severe megablastic anemia; monitor serum potassium, platelet count during therapy. May unmask polycythemia vera. Pregnancy.
May be antagonized by chloramphenicol (when used for treating anemia); monitor and consider alternatives if needed.
Infection, headache, glossitis, paresthesia, asthenia, nausea, rhinitis; anaphylaxis.
Generic Drug Availability:
Single-use nasal spray (0.125mL)—4