Dosage of Vitamin B12 in details
Vitamin B12 Dosage
Applies to the following strength(s): 1000 mcg/mL; 100 mcg/mL; 500 mcg/0.1 mL; 100 mcg; 250 mcg; 500 mcg; 1000 mcg; 50 mcg; 25 mcg/0.1 mL; 2 mcg/mL; 1000 mcg with salcaprozate sodium; 2500 mcg; 5000 mcg
The information at Drugs.com is not a substitute for medical advice. Always consult your doctor or pharmacist.
Usual Adult Dose for:
- Pernicious Anemia
- B12 Nutritional Deficiency
- Schilling Test
Usual Pediatric Dose for:
- Pernicious Anemia
- B12 Nutritional Deficiency
Additional dosage information:
- Renal Dose Adjustments
- Liver Dose Adjustments
- Dose Adjustments
- Precautions
- Dialysis
- Other Comments
Usual Adult Dose for Pernicious Anemia
Parenteral
:
Initial dose: 1000 mcg intramuscularly once a day for 7 days. If there is clinical improvement and a reticulocyte response, 1000 mcg intramuscularly once every other day for 7 days, then once every 3 to 4 days for another 2 to 3 weeks is recommended. Most patients require monthly injections of 100 to 1000 mcg intramuscularly for life.
Nasal Spray or Gel:
Alternatively, Vitamin B12 (Nascobal) nasal spray or nasal gel 500 mcg intranasally to one nostril once a week may be administered to patients with pernicious anemia who require maintenance of normal hematologic status following intramuscular vitamin B12 and who have no nervous system involvement. However, if the patient is not adequately maintained with Vitamin B12 nasal, intramuscular vitamin B12 administration must be resumed.
Usual Adult Dose for B12 Nutritional Deficiency
Oral: 25 to 250 mcg once a day.
Nasal Spray or Gel:
(Nascobal) 500 mcg intranasally in one nostril once a week
(CaloMist) 25 mcg in each nostril once a day (total dose 50 mcg). May be increased to 50 mcg in each nostril once a day.
Usual Adult Dose for Schilling Test
1 mcg radiolabeled Vitamin B12 orally once after urinary voiding. A 24-hour urinary collection is immediately begun. At 2 hours an injection of Vitamin B12 1,000 mcg intramuscularly is given to "flush" the patient of absorbed radiolabeled drug. The percentage of radiolabeled B12 excreted in the urine is a measure of how much labeled drug was absorbed. Normally 7% or more of a dose is excreted in 24 hours (< 7% may be considered a positive Schilling test).
Usual Pediatric Dose for Pernicious Anemia
Neonates and Infants:
Intramuscular or Subcutaneous: 0.2 mcg/kg for 2 days, followed by 1000 mcg/day for 2 to 7 days;
Maintenance: 100 mcg/month.
Children:
Intramuscular or Subcutaneous: 30 to 50 mcg/day for 2 or more weeks (to a total dose of 1000 mcg), then follow with 100 mcg/month.
Usual Pediatric Dose for B12 Nutritional Deficiency
Intramuscular or Subcutaneous: Initial: 0.2 mcg/kg for 2 days followed by 1000 mcg/day for 2 to 7 days followed by 100 mcg/week for a month or 100 mcg/day for 10 to 15 days (total dose of 1 to 1.5 mg), then once or twice weekly for several months. May taper to 60 mcg every month. For malabsorptive causes of B12 deficiency, monthly maintenance doses of 100 mcg have been recommended.
Renal Dose Adjustments
There are no data; however, there are reports of decreased renal elimination of the drug in patients with severe renal insufficiency.
Liver Dose Adjustments
Data not available
Dose Adjustments
Because cobalamin is inexpensive and has few side effects, larger doses may be given, such as 500 to 1000 mcg intramuscularly once a day x 2 weeks, then the same dose twice weekly x 4 weeks or until the hematocrit is normal, then the same dose monthly for life (every 2 weeks if neurological manifestations are present). Other suggested regimens include 1000 mcg intramuscularly once a week x 8 weeks, then once monthly for life.
Precautions
Low initial Vitamin B12 doses combined with potassium supplementation (as needed) may prevent a hypokalemia seen in patients with severe deficiency.
Patients with pernicious anemia are unusually subject to gastric polyps and have approximately twice the normal incidence of stomach cancer. Because of this, some experts recommend frequent stool guaiac examinations and further diagnostic studies when indicated.
In patients suspected of Vitamin B12 sensitivity an intradermal test dose of parenteral Vitamin B12 should be performed prior to initiating therapy with Vitamin B12 nasal spray or gel.
Dialysis
Data not available
Other Comments
Early neurological changes due to B12 deficiency can be rapidly and completely reversed if treatment is begun promptly within the first few weeks of illness. Late neurological changes, such as spinal cord dysfunction, may not improve, but disease progression is usually halted once B12 therapy is begun.
More about Vitamin B12
- Side Effects
- During Pregnancy
- Dosage Information
- Drug Interactions
- Support Group
- 14 Reviews - Add your own review/rating
Consumer resources
- Vitamin B12 (b12)
- Vitamin B12 (b12) chewable tablets
- Vitamin B12 (b12) controlled-release tablets
- Vitamin B12 (b12) spray
- Vitamin B12 (b12) sublingual tablets
- More (6) »
- Other brands: Vitamin B12, Nascobal, B-12, Eligen B12, More (9) »
Professional resources
- B-12 Compliance Injection (FDA)
- More (2) »
Related treatment guides
- B12 Nutritional Deficiency
- Pernicious Anemia
- Schilling Test
- Vitamin B12 Deficiency
What other drugs will affect Vitamin B12?
Before using Vitamin B12, tell your doctor if you are taking any of the following medications:
- antibiotics;
- methotrexate (Rheumatrex);
- pyrimethamine (Daraprim);
- colchicine; or
- if you drank a lot of alcohol within the past 2 weeks.
This list is not complete and there may be other drugs that can interact with Vitamin B12. Tell your doctor about all your prescription and over-the-counter medications, vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start a new medication without telling your doctor.
Vitamin B12 interactions
The effects of some drugs can change if you take other drugs or herbal products at the same time. This can increase your risk for serious side effects or may cause your medications not to work correctly. These drug interactions are possible, but do not always occur. Your doctor or pharmacist can often prevent or manage interactions by changing how you use your medications or by close monitoring.
To help your doctor and pharmacist give you the best care, be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products) before starting treatment with this product. While using this product, do not start, stop, or change the dosage of any other medicines you are using without your doctor's approval.
Some products that may interact with this drug include: drugs that affect the bone marrow (such as chloramphenicol), vitamins/supplements that contain intrinsic factor.
Certain medications can decrease the absorption of vitamin B12, including: colchicine, metformin, extended-release potassium products, antibiotics (such as gentamicin, neomycin, tobramycin), anti-seizure medications (such as phenobarbital, phenytoin, primidone), medications to treat heartburn (such as H2 blockers including cimetidine/famotidine, proton pump inhibitors such as omeprazole/lansoprazole).
Vitamin B12 is an ingredient found in many combination vitamin and nutritional products. Tell your doctor or pharmacist if you are taking other products that contain Vitamin B12, vitamin B12, or Vitamin B12.
Vitamin B12 may interfere with certain laboratory tests (including intrinsic factor, blood tests for other types of anemia), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.
Certain drugs may interfere with laboratory tests for vitamin B12 levels, possibly causing false results. Tell laboratory personnel and all your doctors if you take any of the following: antibiotics (such as amoxicillin, erythromycin), methotrexate, pyrimethamine.
This document does not contain all possible drug interactions. Keep a list of all the products you use. Share this list with your doctor and pharmacist to lessen your risk for serious medication problems.
Reviews
The results of a survey conducted on ndrugs.com for Vitamin B12 are given in detail below. The results of the survey conducted are based on the impressions and views of the website users and consumers taking Vitamin B12. We implore you to kindly base your medical condition or therapeutic choices on the result or test conducted by a physician or licensed medical practitioners.User reports
Consumer reported frequency of use
No survey data has been collected yet4 consumers reported doses
What doses of Vitamin B12 drug you have used?The drug can be in various doses. Most anti-diabetic, anti-hypertensive drugs, pain killers, or antibiotics are in different low and high doses and prescribed by the doctors depending on the severity and demand of the condition suffered by the patient. In our reports, ndrugs.com website users used these doses of Vitamin B12 drug in following percentages. Very few drugs come in a fixed dose or a single dose. Common conditions, like fever, have almost the same doses, e.g., [acetaminophen, 500mg] of drug used by the patient, even though it is available in various doses.
| Users | % | ||
|---|---|---|---|
| 6-10mg | 2 | 50.0% | |
| 201-500mg | 1 | 25.0% | |
| 501mg-1g | 1 | 25.0% | |
Consumer reviews
There are no reviews yet. Be the first to write one! |
Information checked by Dr. Sachin Kumar, MD Pharmacology
