Talk:Levothyroxine
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Alleged Caffeine Interaction
Under "Dosage and Precautions," the article says: "Recently, it has been discovered that caffeine may also interfere with the intestinal absorption of levothyroxine." Yet when you follow the link it leads to an abstract of a study that concludes Coffee may interfere with absorption, not caffeine per se. Although coffee contains a significant caffeine content, that is not all there is to it and other caffeinated beverages (such as tea, or some sodas) often act differently than coffee on the body. The link does not give the full study and even if it did I am not a physician or scientist of any kind so I can't say I would follow it. Is there such a professional out there in wiki-land who has read this study and can confirm that its conclusion is that it is the caffeine in coffee that interferes with absorption? Or cite another study that addresses caffeine specifically? If there isn't, I really think the text should be changed, replacing caffeine with coffee. TheCormac (talk) 14:22, 25 July 2009 (UTC)
Negative formulary
What is a " negative formulary " ? Not much came up on a google search term, is there a citation for this comment? -R 76.248.234.11 (talk) 08:01, 7 September 2008 (UTC)
I believe the negative formulary in this instance might be related to the removal of the drug from a pharmacy formulary, changing the cost status of a drug on formulary or adding / changing utilization of a drug. The later being more likely. --GeoMedrek (talk) 17:33, 2 October 2020 (UTC)
Wrong picture
The picture is definitely wrong. Levothyroxine is derived from the amino acid tyrosine. The nitrogen should be a(n) (alpha) carbon instead, and should have an amino group attached the alpha carbon.
Flip it around
I think that you are looking at the molecule backwards. If you invert it, it looks the same in my opinion. But the only difference that I see is that the carboxylic group is ionized and there is a non-ionic bond with a sodium molecule.
It's the wrong picture and the wrong chemical structure. The medicament is called "levothyroxine SODIUM" and has an Na instead of an H, (which the natural occurring hormone has). — Preceding unsigned comment added by 194.69.213.60 (talk) 09:50, 9 April 2013 (UTC)
- Our articles generally discuss the active moiety of a drug; the sodium is just there for ease of formulation (production) of the drug. Otherwise, we'd need artilces on diclofenac sodium, diclofenac potassium and diclofenac diethylammonium: that just wouldn't be feasible. --ἀνυπόδητος (talk) 18:43, 9 April 2013 (UTC)
Corrected
I believe whatever factual errors there were in this article have been corrected.The molecule is shown in the non-ionized state and there is no sodium atom present.
Here is a more complete and easier to understand page. http://en.wikipedia.org/wiki/Levothyroxine
Completeness
"Levothyroxine" is apparently the name used on prescription bottles for a synthetically manufactured form of thyroxine. However, according to the structure pictured in Wikipedia, the thyroxine manufactured in our bodies (see "Thyroid hormone") is the same (levo-?) isomer, although I didn't find that stated explicitly.
Why doesn't someone who knows indicate in Wikipedia what exactly "Levothyroxine" is, whether it differs at all from our own thyroxine, what "levothyroxine sodium" is, and where it occurs and doesn't occur (naturally and synthetically), so that those of us who don't already know about all this can get an unambiguous take? lifeform (talk)
According to https://www.acs.org/molecule-of-the-week/archive/t/l-thyroxine.html, synthetic levothyroxine is in fact identical to the naturally occurring molecule in human bodies. I believe that dedicating this article exclusively to the synthetic variant without another article for the natural variant is a problem. We can use hydrocortisone and cortisol articles as reference for what to do when a synthetic medication is identical to the natural one. errata-c (talk) — Preceding undated comment added 18:03, 19 January 2024 (UTC)
Marketing and Approval
The report referred to "various complaints" during the 1990s which led to the FDA reviewing Synthroid, and it needed citation. The only citation I could find was WorstPills.org, which cited scientific studies concerned about Synthroid's effectiveness versus the effectiveness of other levothyroxines. I am not entirely convinced of "WorstPills"'s impartiality, but it was the only resource I can find. If someone can find a better citation, it would be much appreciated. 70.187.186.35 08:57, 23 July 2007 (UTC)
- FDA approves first levothyroxine preparation Enforcement against unlicenced levothyroxine products the article is I think confused here. There are two separate items being mixed up. There was a complaint that the manufacturers of synthroid suppressed research that showed they were no better than generics. There was a second issue that levothyroxine preparations were not properly stable, resulting in recalls. The FDA required a NDA (new drug application) to resolve the second of these issues, which led to synthroid (amongst others) being reformulated to improve its stability. Mary Shomon's site covered both stories in depth at the time, and I'm sure more details can be found in the archives at thyroid.about.com if needed. —Preceding unsigned comment added by 84.45.158.52 (talk) 23:58, 11 April 2009 (UTC)
Shouldn't this be in Category:Thyroid hormones? Schissel | Sound the Note! 14:33, 27 April 2009 (UTC)
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Adverse Effects
This section reads like a medical advice page and not an encyclopedia. The lines suggesting what to do if you have allergies, are lactose intolerant, etc. should probably be cleaned up 69.245.54.30 (talk) 13:40, 9 July 2010 (UTC)
- Working on this stuff right now. Persephone12 (talk) 01:27, 19 July 2010 (UTC)
veterinarian use
The present paragraph mentions dogs get point one milligrams for 10 pounds of body weight. That's about 30 times more than I get per my human poundage, so I was wondering if that was correct or if it was meant to be micrograms or another number? Tullywinters (talk) 10:45, 31 July 2011 (UTC)
Official naming
The official International Nonproprietary Name (INN) for levothyorxine is actually 'levothyroxine sodium' - http://mednet.who.int/ViewINN.aspx?c=1f216b1a-c080-46a1-9a39-c33717387926&i=453 Since this article is referring to the pharmaceutical product shouldn't it reference to actual official name? Daunorubicin (talk) 11:04, 18 September 2012 (UTC)
- Support per WP:MOSMED#Drugs, medications and devices. This seems to be one of the rare cases (apart from quaternary cations) where the INN names the salt. --ἀνυπόδητος (talk) 12:12, 18 September 2012 (UTC)
Grapefruit study sample
"Grapefruit juice may delay the absorption of levothyroxine, but it is not believed to have a significant effect on bioavailability." The study cited (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1884777/) used a sample of 10 healthy people aged 20-30, 8 males and 2 females. A quick google search indicates that thyroid problems are more common among women and the elderly, so the sample is almost the opposite of the most-affected population. A more thorough study on grapefruit-drug interactions (http://www.cmaj.ca/content/early/2012/11/26/cmaj.120951) states that "Patient vulnerability...varies markedly." "....a pronounced pharmacokinetic interaction has been shown to occur in patients older than 70 years. Furthermore, older adults can have decreased capacity to compensate for excessive systemic drug concentrations."
Article should indicate that the study was limited to 8 young men and 2 young women, and thus cannot make any conclusions about the effect of grapefruit, pomelo, and related fruits on the absorption of levothyroxine in elderly patients. A Michener (talk) 18:45, 7 December 2013 (UTC)
Without food or beverage other than water Isn't the levothyroxine to be taken with only water at least one half hour BEFORE any other beverage or food; therefore, levothyroxine is to be taken without food or beverage (other than water)? MaynardClark (talk) 12:00, 29 June 2018 (UTC)
There is content at the AfC that could be merged into this article. If done, ping me and I will look at a history merge. Dlohcierekim 01:41, 3 January 2014 (UTC)
Poor, confusing sentence
The following sentence is gramatically strange and confusing: "Ketamine may cause hypertension and tachycardia and tricyclic and tetracyclic antidepressants increase its toxicity." — Preceding unsigned comment added by 84.215.227.251 (talk) 10:10, 13 March 2014 (UTC)
- Thanks for the heads-up! I fixed this, more or less, but the interactions section is still pretty bad – contains lots of things based on tiny studies. --ἀνυπόδητος (talk) 19:31, 13 March 2014 (UTC)
Formula
It seems that NO4 is missing in the formula.
Simon de Danser (talk) 11:55, 29 June 2018 (UTC)
- Fixed. Thanks for catching this! --ἀνυπόδητος (talk) 06:07, 30 June 2018 (UTC)
why so heavily prescribed ?
why is this drug the second most popular prescription ? is that condition hypothyroidism THAT common ?--— ⦿⨦⨀Tumadoireacht Talk/Stalk 00:36, 23 January 2022 (UTC)