hydroxocobalamin

Necessary coenzyme for metabolic processes, including fat and carbohydrate metabolism and protein synthesis.
Required for cell reproduction and hematopoiesis.

Therapeutic effects:

Corrects manifestations of pernicious anemia (megaloblastic indices, GI lesions, and neurologic damage).
Corrects vitamin B₁₂ deficiency.
Reverses symptoms of cyanide toxicity.

Pharmacokinetics ⬆ ⬇

Absorption: Significant protein binding occurs after intravenous administration.

Distribution: Unknown.

Metabolism/Excretion: Primarily excreted unchanged in urine.

Half-Life: 26–31 hr.

Time/Action Profile ⬆ ⬇

(reticulocytosis)

ROUTE	ONSET	PEAK	DURATION
IM	unknown	unknown	unknown

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity;
Lactation: Cyanokit: Breastfeeding not recommended.

Use Cautiously in:

IM injection: Uremia, folic acid deficiency, concurrent infection, iron deficiency (response to vitamin B₁₂ will be impaired);
Pedi: Cyanokit: Safety and effectiveness not established;
OB: Cyanokit: Use during pregnancy only if potential maternal benefit outweighs potential fetal risk.

Adv. Reactions/Side Effects ⬆ ⬇

IM injection

Derm: itching

F and E: hypokalemia

GI: diarrhea

Local: pain at IM site

Misc: HYPERSENSITIVITY REACTIONS (INCLUDING ANAPHYLAXIS)

Cyanokit

CV: hypertension, chest pain, edema, tachycardia

Derm: erythema, rash, pruritus, urticaria

EENT: dry throat, eye redness, eye swelling

GI: abdominal discomfort, diarrhea, dyspepsia, dysphagia, hematochezia, nausea, vomiting

GU: red urine, acute renal failure

Local: injection site reaction

Neuro: dizziness, headache, memory impairment, restlessness

Resp: dyspnea

Interactions ⬆ ⬇

For IM injection only

Drug-drug:

Chloramphenicol and antineoplastics may ↓ hematologic response to vitamin B₁₂.
Colchicine, aminosalicylic acid, or excessive intake of alcohol, or vitamin C may ↓ absorption/effectiveness of vitamin B₁₂.

Route/Dosage ⬆ ⬇

Vitamin B12 Deficiency (IM only)

Pernicious Anemia (IM only)

Schilling Test

Cyanide Poisoning (Cyanokit only)

IM (Adults ): 30 mcg/day for 5–10 days, then 100–200 mcg/mo.
IM (Children ): 100 mcg/day for 2 or more wk (to achieve total dose of 1000–5000 mcg), then 30–50 mcg/mo.
IM (Adults ): 100 mcg/day for 6–7 days; if improvement, give same dose every other day for 7 doses, then every 3–4 days for 2–3 wk; once hematologic values return to normal (remission), give maintenance dose of 100 mcg/mo.
IM (Children ): 30–50 mcg/day for 2 or more wk (to achieve total dose of 1000–5000 mcg), then 100 mcg/mo.
IM SC (Adults ): Flushing dose is 1000 mcg.
IV (Adults ): 5 g over 15 min; another 5 g dose may be infused over 15–120 min depending upon severity of poisoning (maximum cumulative dose = 10 g).

Availability ⬆ ⬇

Powder for injection (Cyanokit) (requires reconstitution and dilution): 5 g/vial
Solution for injection: 1000 mcg/mL

Assessment ⬆ ⬇

Assess patient for signs of vitamin B₁₂ deficiency (pallor; neuropathy; psychosis; red, inflamed tongue) before and periodically during therapy.
Cyanokit: Management of cyanide poisoning should also include establishment of airway, ensuring adequate oxygenation and hydration, cardiovascular support, and seizure management. Monitor BP and HR continuously during and after infusion and immediately report significant changes. The maximal ↑ in BP usually occurs toward the end of the infusion. BP usually returns to baseline within 4 hr of drug administration.

Lab Test Considerations:

Anemia: Monitor blood smear, red cell indices, plasma folic acid, vitamin B₁₂, and iron levels, hemoglobin, hematocrit, and reticulocyte count before treatment, after 5–7 days of therapy, 1 mo after the start of therapy, and then every 3–6 mo. Evaluate serum potassium level in patients receiving vitamin B₁₂ for pernicious anemia for hypokalemia during the first 48 hr of treatment. Serum potassium levels and platelet counts should be monitored routinely during the course of therapy.
Cyanide Poisoning: Monitor CBC, arterial and venous blood gases, serum electrolytes and lactate, renal function, and whole blood cyanide levels.

Implementation ⬆ ⬇

Y-Site Incompatibility:

Usually administered in combination with other vitamins; solitary vitamin B₁₂ deficiencies are rare.
- Administration of vitamin B₁₂ by the oral route is useful only for nutritional deficiencies. Patients with small-bowel disease, malabsorption syndrome, or gastric or ileal resections require parenteral administration.
IM: Vials should be protected from light.
- If SUBQ route used, deep SUBQ administration is preferred.
Intermittent Infusion: Reconstitute each 5 g vial with 200 mL of 0.9% NaCl, D5W, or LR. Gently invert the vial for at least 60 sec prior to infusion. Do not shake. Reconstituted vial can be hung for infusion. Solution is clear dark red; do not administer solutions that are discolored or contain particulate matter.
- Reconstituted solutions are stable for 6 hr at room temperature. Discard any unused solution after 6 hr.
Rate: Administer initial 5–g dose over 15 min. Administer additional 5–g dose over 15–120 min.

Patient/Family Teaching ⬆ ⬇

Intermittent Infusion:

Encourage patient to comply with diet recommendations of health care professional. Explain that the best source of vitamins is a well-balanced diet with foods from the four basic food groups.
Foods high in vitamin B₁₂ include meats, seafood, egg yolk, and fermented cheeses; few vitamins are lost with ordinary cooking.
Patients self-medicating with vitamin supplements should be cautioned not to exceed RDA. Effectiveness of megadoses for treatment of various medical conditions is unproved and may cause side effects.
Inform patients with pernicious anemia of the lifelong need for vitamin B₁₂ replacement.
Emphasize the importance of follow-up exams to evaluate progress.

Evaluation/Desired Outcomes ⬆ ⬇

Resolution of the symptoms of vitamin B₁₂ deficiency.
- Increase in reticulocyte count.
Improvement in manifestations of pernicious anemia.
Resolution of symptoms of cyanide poisoning.

US Brand Names ⬆ ⬇

Code ⬆

NDC Code

0591- Actavis Pharma, Inc.
- 0591-2888- Hydroxocobalamin
  - 0591-2888-30- 1 VIAL, MULTI-DOSE in 1 CARTON (0591-2888-30) > 30 mL in 1 VIAL, MULTI-DOSE

11704- Meridian Medical Technologies, Inc.
- 11704-370- Cyanokit
  - 11704-370-01- 1 VIAL, GLASS in 1 CARTON (11704-370-01) > 250 mL in 1 VIAL, GLASS

50090- A-S Medication Solutions
- 50090-3548- Hydroxocobalamin
  - 50090-3548-0- 1 VIAL, MULTI-DOSE in 1 CARTON (50090-3548-0) > 30 mL in 1 VIAL, MULTI-DOSE

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇