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Levothyroxine Therapy
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
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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 Unpublished letters cannot be returned.
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TO THE EDITOR:
In the review by Mandel and colleagues [1] on levothyroxine therapy, activated charcoal was omitted from the list of conditions affecting levothyroxine requirements by interfering with intestinal absorption [2]. By contrast, evidence in favor of interference with levothyroxine pharmacokinetics by lovastatin is weak [3].
The suggestion to separate by at least 3 hours the administration of levothyroxine from administration of medications that may interfere with its intestinal absorption could be risky because thyroxine undergoes enterohepatic circulation [4]. In our experience, separating the administration of an aluminum hydroxide from that of levothyroxine does not prevent considerable increase in serum levels of thyroid-stimulating hormone (TSH) [5]. Administration of levothyroxine and cholestyramine produced a marked increase in serum TSH in another patient, despite a minimum 4-hour separation between times of ingestion. I strongly agree with the suggestion to monitor thyroid function tests 1 month after initiation (or cessation) of drugs that affect levothyroxine requirements.
Yair Liel, MD
Soroka Medical Center; Ben-Gurion University of the Negev; Beer Sheva, Israel
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.
- Copyright ©2004 by the American College of Physicians
