The prescribing information for cyanocobalamin injection (a repackager's label of the approved product) lists a contraindication and several warnings. Each names the people or circumstances it is about, and this guide sets them out as the label words them. A further statement comes from the label of a different product, a nasal spray, and is kept apart.
The contraindication and the warnings
The table gives each statement, who the label says it is about, and what it says.
| Topic | Who the label says it is about | What the label says |
|---|---|---|
| Contraindication | Sensitivity to cobalt and/or vitamin B12. | The label lists sensitivity to cobalt and/or vitamin B12 as a contraindication. |
| Leber's disease | Patients with early Leber's disease (hereditary optic nerve atrophy) who were treated with cyanocobalamin. | The prescribing information warns that they suffered severe and swift optic atrophy. |
| Hypokalemia and sudden death | Severe megaloblastic anemia which is treated intensely. | The prescribing information warns that hypokalemia and sudden death may occur. |
| Anaphylactic shock | Reports after parenteral vitamin B12 administration. The test dose statement is about patients suspected of being sensitive to the drug. | The prescribing information says anaphylactic shock and death have been reported after parenteral vitamin B12 administration. It recommends an intradermal test dose before the injection is administered to patients suspected of being sensitive. |
| Benzyl alcohol | Premature infants. | The prescribing information says the product contains benzyl alcohol, which has been reported to be associated with a fatal "Gasping Syndrome" in premature infants. |
| Aluminum | Prolonged parenteral administration when kidney function is impaired. | The prescribing information says the product contains aluminum that may be toxic, and that aluminum may reach toxic levels with prolonged parenteral administration if kidney function is impaired. |
| Folic acid in place of B12 | Patients taking folic acid in place of vitamin B12. | The prescribing information says patients should be warned about this danger, because folic acid may prevent anemia but allow progression of subacute combined degeneration. |
How the warnings are framed
Some statements name a group of patients, such as patients with early Leber's disease or, for benzyl alcohol, premature infants. Others name a circumstance, such as severe megaloblastic anemia which is treated intensely or prolonged parenteral administration when kidney function is impaired. Another concerns a substitution: folic acid taken in place of vitamin B12.
The anaphylaxis statement is different again. It reports events after parenteral vitamin B12 administration and recommends an intradermal test dose only for patients suspected of being sensitive to the drug. As quoted here, none of these statements gives the number of patients affected.
Other statements on the label
On overdosage, the prescribing information states that no overdosage has been reported with this drug. That sentence says what has been reported. It is not a statement that no harm can occur, and the warnings above are part of the same label.
On inspection, the prescribing information says parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. That statement is about the product and its container, not about a group of patients.
A statement from the nasal spray label
The Nascobal (cyanocobalamin nasal spray) label, not the injection label, states that hypokalemia and thrombocytosis can occur upon conversion of severe megaloblastic anemia to normal erythropoiesis. It is listed here because it covers similar ground to the injection label's hypokalemia warning. It is a statement about a different product, and this guide does not say that the injection label makes it.
What this does not tell you
This guide repeats the label's words. The statements quoted give no figures for how often any of these events occur, and they cannot tell you whether a warning applies to you. A licensed provider decides that.
These statements come from the label of an approved cyanocobalamin injection. An FDA page states that compounded drugs are not FDA-approved, which means FDA does not verify the safety, effectiveness or quality of compounded drugs before they are marketed. So these statements describe the label they come from, not any compounded preparation.