Module 4: Oral Vitamin B12

Question 1

What is the drug name for oral vitamin b12?

Answer 1

Cyanocobalamin

Question 2

What are common indications for cyanocobalamin?

Answer 2

Vit B12 deficiency: Tx of prenicious anemia or vit B12 deficiency

Prevention of deficiency in pt’s with increased requirements (pregnancy, hemorrhage)

Question 3

What is the MOA?

Answer 3

Coenzyme for various metabolic functions, including fat and carbohydrate metabolism and protein synthesis, used in cell replication and hematopoiesis.

Question 4

What are pharmacokinetic considerations?

Answer 4

A: Variable form the terminal ileum; requires the presence of calcium and gastric ‘intrinsic factor’ to transfer the compound across the intestinal mucosa

D: Principally stored in the liver and bone marrow, also stored in the kidneys and adrenals. Protein binding = transobalamins

M: Converted in tissues to active coenzymes

E: urine

Question 5

What are special prescribing considerations?

Answer 5

• Leber disease
• Megaloblastic anemia
• polycythemia vera

Question 6

What are pregnancy and lactation recommendations?

Answer 6

Safe

Question 7

What are common or severe adverse effects?

Answer 7

N/A

Question 8

Significant drug interactions?

Answer 8

None

Question 9

What are contraindications/ cautions?

Answer 9

Contraindicated:
- avoid preparations containing benzyl alcohol in premature infants

Cautions:
- hereditary optic nerve atrophy
- renal impairment
Uremia, folic acid deficiency, concurrent infection, iron deficiency (response to vit B12 will be impaired)

Question 10

What are monitoring parameters?

Answer 10

Vit B12
Hgb
HCT
erythrocyte and reticulocyte count
Serum folate and iron levels