REPLY
Letters: Omeprazole and Vitamin B12
Stefan P. Marcuard, MD
1 July 1994 | Volume 121 Issue 1 | Page 74
IN RESPONSE:
Our study design to evaluate protein-bound B12 absorption before and during treatment with omeprazole is appropriate and is known as "self-pairing" [1, 2]. This method eliminates the variability between study patients and "controls." Although we agree that a placebo group would have strengthened our results, our straightforward study design is adequate to show changes in vitamin B12 absorption during omeprazole therapy.
Dr. Lavy's comments indicate a misunderstanding of vitamin B12 digestion and absorption. To correct protein-bound vitamin B12 malabsorption, hydrochloric acid (not vitamin B12) is added to the modified Schilling tests. In fact, this has been done by other investigators who showed a correction of protein-bound cyanocobalamin malabsorption by hydrochloric acid [3]. Although we found considerable variation in protein-bound cyanocobalamin absorption at baseline, it is noteworthy that the absorption decreased for each study patient during omeprazole therapy [4].
Finally, the effect of omeprazole on cyanocobalamin absorption is not unique, given that a similar effect has been described in hypochlorhydria or achlorhydria caused by histamine-2-receptor antagonists and occurring after vagotomy [4].
|
Author and Article Information
|
|---|
East Carolina University School of Medicine; Greenville, NC 27858-4354
1. Louis TA, Lavori PW, Bailar JC, Polansky M. Crossover and self-controlled designs in clinical research. In: Bailar JC, Mosteller F, eds. Medical Uses of Statistics. Waltham, Massachusetts: NEJM Books; 1986:67-90.
2. Colton T. Paired samples. In: Colton T, ed. Statistics in Medicine. Boston: Little, Brown; 1974:131-6.
3. Kemp JA, Golner BB, Russell RM. Effect of an acidic dietary drink on absorption of protein-bound vitamin B12 (Abstract). Gastroenterology. 1992; 102:560A.
4. Marcuard, SP, Albernaz L, Khazanie PG. Omeprazole therapy causes malabsorption of cyanocobalamin (vitamin B12). Ann Intern Med. 1994; 120:211-5.[Abstract/Free Full Text]
About Letters
The Editors welcome submissions for possible publication in the Letters section. Authors of letters should:
•Include no more than 300 words of text, three authors, and five references
•Type with double-spacing
•Send three copies of the letter, an authors' form signed by all authors, and a cover letter describing any conflicts of interest related to the contents of the letter.
Letters commenting on an Annals article will be considered if they are received within 6 weeks of the time the article was published. Only some of the letters received can be published. Published letters are edited and may be shortened; tables and figures are included only selectively. Authors will be notified that the letter has been received. If the letter is selected for publication, the author will be notified about 3 weeks before the publication date. Unpublished letters cannot be returned.
Annals welcomes electronically submitted letters.
Top
Author & Article Info
References
Article
