Pernicious Anemia Medication

  • Author: Paul Schick, MD; Chief Editor: Emmanuel C Besa, MD   more...
 
Updated: Dec 8, 2011
 

Medication Summary

Vitamin B-12 is available for therapeutic use parenterally as either cyanocobalamin or hydroxocobalamin.[5] Both are equally useful in the treatment of vitamin B-12 deficiency, and they are nontoxic (except for rare allergic reactions). Theoretical advantages exist to using hydroxocobalamin because it is retained better in the body and is more available to cells; both chemical forms of cobalamin provide prompt correction.

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Vitamins

Class Summary

Cobalamin is an essential vitamin. The inability to absorb adequate quantities of the vitamin from the diet leads to hematologic and neurologic complications.

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Cyanocobalamin (CaloMist, Ener-G, Nascobal)

 

Deoxyadenosylcobalamin and hydroxocobalamin are active forms of vitamin B-12 in humans. Microbes, but not humans or plants, synthesize vitamin B-12. Vitamin B-12 deficiency may result from intrinsic factor (IF) deficiency (pernicious anemia), partial or total gastrectomy, or diseases of the distal ileum.

Cyanocobalamin may be administered either intramuscularly (IM) or subcutaneously (SC). At the initiation of therapy, large daily doses are administered in order to replenish body stores with cobalamin.

With certain hereditary defects of cobalamin, metabolism doses of cobalamin (eg, 1000 µg SC every week) may be required to obtain a response.

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Hydroxocobalamin

 

Deoxyadenosylcobalamin and hydroxocobalamin are active forms of vitamin B-12 in humans. Vitamin B-12 synthesized by microbes but not humans or plants. Vitamin B-12 deficiency may result from intrinsic factor deficiency (pernicious anemia), partial or total gastrectomy, or diseases of the distal ileum. This agent is used to treat conditions caused by altered cobalamin metabolism that may cause secondary carnitine deficiency (ie, cobalamin C deficiency).

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Multivitamins (MVI-12, Cernevit-12)

 

Multivitamins are used as dietary supplements.

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Contributor Information and Disclosures
Author

Paul Schick, MD  Emeritus Professor, Department of Internal Medicine, Jefferson Medical College of Thomas Jefferson University; Research Professor, Department of Internal Medicine, Drexel University College of Medicine; Adjunct Professor of Medicine, Lankenau Hospital

Paul Schick, MD is a member of the following medical societies: American College of Physicians, American Heart Association, American Society of Hematology, International Society on Thrombosis and Haemostasis, and New York Academy of Sciences

Disclosure: Nothing to disclose.

Coauthor(s)

Marcel E Conrad, MD  Distinguished Professor of Medicine (Retired), University of South Alabama College of Medicine

Marcel E Conrad, MD is a member of the following medical societies: Alpha Omega Alpha, American Association for the Advancement of Science, American Association of Blood Banks, American Chemical Society, American College of Physicians, American Physiological Society, American Society for Clinical Investigation, American Society of Hematology, Association of American Physicians, Association of Military Surgeons of the US, International Society of Hematology, Society for Experimental Biology and Medicine, and Southwest Oncology Group

Disclosure: No financial interests None None

Chief Editor

Emmanuel C Besa, MD  Professor, Department of Medicine, Division of Hematologic Malignancies, Kimmel Cancer Center, Jefferson Medical College of Thomas Jefferson University

Emmanuel C Besa, MD is a member of the following medical societies: American Association for Cancer Education, American College of Clinical Pharmacology, American Federation for Medical Research, American Society of Clinical Oncology, American Society of Hematology, and New York Academy of Sciences

Disclosure: Nothing to disclose.

Additional Contributors

David Aboulafia, MD Medical Director, Bailey-Boushay House, Clinical Professor, Department of Medicine, Division of Hematology, Attending Physician, Section of Hematology/Oncology, Virginia Mason Clinic; Investigator, Virginia Mason Community Clinic Oncology Program/SWOG

David Aboulafia, MD is a member of the following medical societies: American College of Physicians, American Medical Association, American Medical Directors Association, American Society of Hematology, Infectious Diseases Society of America, and Phi Beta Kappa

Disclosure: Nothing to disclose.

Troy H Guthrie, Jr, MD Director of Cancer Institute, Baptist Medical Center

Troy H Guthrie, Jr, MD is a member of the following medical societies: American Federation for Medical Research, American Medical Association, American Society of Hematology, Florida Medical Association, Medical Association of Georgia, and Southern Medical Association

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: eMedicine Salary Employment

References

  1. Hoffman R, Benz EJ, Furie B, Shattil SJ. Hematology: Basic Principles and Practice. Philadelphia, Pa: Churchill Livingstone; 2009.

  2. Elmadfa I, Singer I. Vitamin B-12 and homocysteine status among vegetarians: a global perspective. Am J Clin Nutr. May 2009;89(5):1693S-1698S. [Medline].

  3. Chan JC, Liu HS, Kho BC, Lau TK, Li VL, Chan FH, et al. Longitudinal study of Chinese patients with pernicious anaemia. Postgrad Med J. Dec 2008;84(998):644-50. [Medline].

  4. Andrès E, Vogel T, Federici L, Zimmer J, Ciobanu E, Kaltenbach G. Cobalamin deficiency in elderly patients: a personal view. Curr Gerontol Geriatr Res. 2008;848267. [Medline].

  5. Erkurt MA, Aydogdu I, Dikilitas M, Kuku I, Kaya E, Bayraktar N, et al. Effects of cyanocobalamin on immunity in patients with pernicious anemia. Med Princ Pract. 2008;17(2):131-5. [Medline].

 
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Pernicious anemia. The structure of cyanocobalamin is depicted. The cyanide (Cn) is in green. Other forms of cobalamin (Cbl) include hydroxocobalamin (OHCbl), methylcobalamin (MeCbl), and deoxyadenosylcobalamin (AdoCbl). In these forms, the beta-group is substituted for Cn. The corrin ring with a central cobalt atom is shown in red and the benzimidazole unit in blue. The corrin ring has 4 pyrroles, which bind to the cobalt atom. The fifth substituent is a derivative of dimethylbenzimidazole. The sixth substituent can be Cn, CC3, hydroxycorticosteroid (OH), or deoxyadenosyl. The cobalt atom can be in a +1, +2, or +3 oxidation state. In hydroxocobalamin, it is in the +3 state. The cobalt atom is reduced in a nicotinamide adenine dinucleotide (NADH)–dependent reaction to yield the active coenzyme. It catalyzes 2 types of reactions, which involve either rearrangements (conversion of l methylmalonyl coenzyme A [CoA] to succinyl CoA) or methylation (synthesis of methionine).
Pernicious anemia. Inherited disorders of cobalamin (Cbl) metabolism are depicted. The numbers and letters correspond to the sites at which abnormalities have been identified, as follows: (1) absence of intrinsic factor (IF); (2) abnormal Cbl intestinal adsorption; and (3) abnormal transcobalamin II (TC II), (a) mitochondrial Cbl reduction (Cbl A), (b) cobalamin adenosyl transferase (Cbl B), (c and d) cytosolic Cbl metabolism (Cbl C and D), (e and g) methyl transferase Cbl utilization (Cbl E and G), and (f) lysosomal Cbl efflux (Cbl F).
Pernicious anemia. Cobalamin (Cbl) is freed from meat in the acidic milieu of the stomach where it binds R factors in competition with intrinsic factor (IF). Cbl is freed from R factors in the duodenum by proteolytic digestion of the R factors by pancreatic enzymes. The IF-Cbl complex transits to the ileum where it is bound to ileal receptors. The IF-Cbl enters the ileal absorptive cell, and the Cbl is released and enters the plasma. In the plasma, the Cbl is bound to transcobalamin II (TC II), which delivers the complex to nonintestinal cells. In these cells, Cbl is freed from the transport protein.
Peripheral smear of blood from a patient with pernicious anemia. Macrocytes are observed, and some of the red blood cells show ovalocytosis. A 6-lobed polymorphonuclear leucocyte is present.
Bone marrow aspirate from a patient with untreated pernicious anemia. Megaloblastic maturation of erythroid precursors is shown. Two megaloblasts occupy the center of the slide with a megaloblastic normoblast above.
Response to therapy with cobalamin (Cbl) in a previously untreated patient with pernicious anemia. A reticulocytosis occurs within 5 days after an injection of 1000 mcg of Cbl. This lasts for about 2 weeks after injection. The hemoglobin (Hgb) concentration increases at a slower rate because many of the reticulocytes are abnormal and do not survive as mature erythrocytes.
Table 1. Serum Methylmalonic Acid and Homocysteine Values Used in Differentiating Between Cobalamin and Folic Acid Deficiency
Patient ConditionMethylmalonic AcidHomocysteine
HealthyNormalNormal
Vitamin B-12 deficiencyElevatedElevated
Folate deficiencyNormalElevated
Table 2. Schilling Test Results
Patient ConditionStage I



Water



Stage II



Intrinsic Factor



Stage III



Antibiotic



Stage IV



Pancreatic Extract



HealthyNormal………
Pernicious anemiaLowNormal……
Bacterial overgrowthLowLowNormal…
Pancreatic insufficiencyLowLowLowNormal
Defect in ileumLowLowLowLow
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