Long-term trial of oral vitamin B12 in pernicious anaemia

Oral cobalamin remains medicine's best kept secret

A cross-sectional survey was conducted in order to describe the use of oral cobalamin among geriatricians, hematologists, and general practitioners, and to explore factors related to its use. The study population consisted of all geriatricians (n = 138) and hematologists (n = 317) listed in the Canadian Medical Directory plus a random sample of 307 general practitioners. The overall response rate was 40%. Intramuscular and oral cobalamin was prescribed by 76 and 32% of the respondents, respectively. Twenty seven percent reported using both oral and intramuscular cobalamin and 6% reported using only oral cobalamin. Only 25% of respondents indicated they were aware of a RCT demonstrating the efficacy of oral cobalamin prior to reading a synopsis of the study in the survey. After multivariate adjustment, only the belief that oral cobalamin was effective and certainty about who carried oral preparations remained independently associated with oral cobalamin use. Oral cobalamin has been shown to be an efficacious, cost efficient and safe method of treating cobalamin deficiency. Nonetheless, it is not used by the majority of physicians treating this condition. Strategies to promote the use of oral cobalamin should be directed at educating physicians of its efficacy and providing them with prescribing information on where it can be purchased.

Treatment of vitamin b(12)-deficiency anemia: oral versus parenteral therapy

OBJECTIVE

To evaluate the use of oral cyanocobalamin therapy in the treatment of cobalamin (vitamin B(12))-deficient anemia.

DATA SOURCES

Primary and review articles were identified by MEDLINE search (1966-May 2000) and through secondary sources.

DATA SYNTHESIS

Cobalamin-deficient anemia is among the most common diagnoses in older populations. Cobalamin-deficient anemia may be diagnosed as pernicious anemia, resulting from the lack of intrinsic factor required for cobalamin absorption or as protein malabsorption from the inability to displace cobalamin from protein food sources. Several studies provide evidence that daily oral cyanocobalamin as opposed to monthly parenteral formulations may adequately treat both types of cobalamin-deficient anemias.

CONCLUSIONS

Daily oral cyanocobalamin at doses of 1000-2000 microg can be used for treatment in most cobalamin-deficient patients who can tolerate oral supplementation. There are inadequate data at the present time to support the use of oral cyanocobalamin replacement in patients with severe neurologic involvement.

Pernicious anemia revisited

OBJECTIVE

We discuss the pathophysiologic mechanisms, clinical features, diagnosis, and treatment of pernicious anemia (PA).

DESIGN

A review of the clinical applications of the diagnostic and therapeutic progress of PA is presented.

MATERIAL AND METHODS

A patient with PA may have a wide range of initial complaints that affect various organ systems or may be entirely asymptomatic. Hematologic variables may be normal in patients with cobalamin (Cbl) deficiency. Because of the difficulties in diagnosing Cbl deficiency, alternatives to measuring Cbl have been sought. Determining the urinary methylmalonic acid level is a less invasive, more practical, and, possibly, more sensitive method. The Schilling test is performed for assessment of the absorption of orally ingested radiolabeled crystalline cyano-Cbl; results should be interpreted cautiously.

RESULTS

Vitamin B12 therapy should be lifelong. It is customarily administered intramuscularly. Other routes of administration have been studied.

CONCLUSION

PA is one of the most treatable hematologic disorders.