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December 01, 2007


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I am a manufacturer of blood collection tubes . I want to know where I can get commercial pro-coagulant reagents.

Warfarin has many, many interactions with drugs, foods and supplements, including multivitamins (some can contain large amounts of vitamin K). However, this doesn’t mean that you should stop eating vitamin K-containing products or shellfish. The most important rule is to be consistent with your diet and supplements. When on warfarin, it may take some time before your INR is stable (this is the number to show that warfarin is effective). If someone is constantly changing his/her diet or medications, then the INR can shift in either direction causing too much anti-coagulation or not enough. It’s actually been shown that patients eating consistent diets with a lot of vitamin K had more stable INRs than patients that tried to avoid these foods. So the lesson here is to eat consistently and be aware of any changes!

Speaking of warfarin/coumadin, it is quite well-known in the drug interactions circuit. The pharmacokinetic mechanisms for drug interactions with coumadin are mainly enzyme induction, enzyme inhibition and reduced plasma protein binding, and if you want an idea of the potential drug interactions that might occur with warfarin, scroll down this page: http://www.rxlist.com/cgi/generic/warfarin_ad.htm

In any case, these interactions are impossible to avoid, as all it takes to avoid a rise in your PT/INR levels is to carefully plan your medication regimen with your doctor, as well as be sure to avoid mixing and matching between potentially harmful foods/medications in your daily routine.

Enjoy your seafood.

With all the talk about chitosan-containing products (bandages, aftershave, etc.), I began to wonder about the effects of these products on individuals with shellfish allergies. I found out that the makers of at least one of the chitosan-containing bandages states that their product does not cause allergic reactions, even in those with shellfish allergy, because the compound does not contain the offending protein. Interesting! But I think I would still want to use these with caution if I was allergic to shellfish!

Caffeinated beverages should also be avoided in patients taking coumadin. I'm not quite sure why though.

Chitosan is produced by deacetylating chitin, which is the main component of exoskeletons (of crabs, shrimp, beetles, etc.). Since a chemical process is required to derive chitosan from chitin, I don't think that eating a few soft shelled crabs will have significant effects on anticoagulation. The amount of vitamin K in the diet is a bigger concern for people on Coumadin; for it to work consistently, patients should be consistent with their dietary intake of vitamin k.

Chitosan's stickiness has been exploited commercially in many applications. Filtration is one - it just absorbs all the junk and can remove contaminants from water. It's also used in landscaping with fertilizer to help retain water. Plus, it's non-toxic and biodegradable, so won't harm the environment.

Super glue is great - I keep it around for paper cuts too! But the potential advantage of chitosan is that it could be used in brain surgery, to repair nerves, etc. I wouldn't want to be using super glue for that :)

Skin bonding substances have been around for decades - one of the first intended uses for super glue was for skin closure (or so I've heard). I've been using super glue for years to seal paper cuts. Once I had to get stitches on my face and the doctors used a super glue-like substance called Dermabond. It was great.

Check out this cool new use for chitosan:

Chitosan can be used in place of sutures. no more stitches!

Apologies for the late reply:

I see lots of confusion in all these comments. Let me clarify one by one. First of all, chitosan is a very generic name, and the properties of it varies depending on the degree of deacetylation and molecular weight. So the functions, such as pro-coagulation, anti-coagulation, hypocholestermic, hypercholestermic, etc., are all possible if you know how to manipulate chitosan's structure properly.

1) Chitosan is a pro-coagulant.

This is due to the highly Positive charge associated with chitosan molecules when dissolved in acids. RBCs, platelets in blood are negatively charged, and this charge difference actually clots the blood. As someone commented, it becomes extremely sticky when it comes in contact with blood. The US army is selling a product with the same property at $100 per 10cm piece. It is so expensive due to the process involved in procuring the pure grade chitosan (refers to right proportion of DDA and mol. wt without variation).

Though the molecular mechanism of chitosan molecules interaction with blood is not fully understood, it is a well known fact that chitosan initiates temporary clotting of blood by bypassing the natural clotting mechanism. So it can be used for patients with bleeding disorders too.

2) Chitosan as a fat blocker.

An empirically proved fact is that chitosan binds to negatively charged fat molecules in the intestine and prevents absorption through nephrones. But as the breakdown mechanism is not fully understood, the FDA hasn't given permission to market it yet.


I'm a shrimp lover, and I have't come across any of those experiences yet. But let me quote few historical evidences.
1) It is documented that decades back few nomads living in some islands, used to rub shell of crabs, shrimp, etc. on their wounds, and it used to stop bleeding instantly.
2) It is said (not proved) that crabs won't bleed to death even when its legs are pulled out. This may be because of the chitin in their shells.. who knows!!

Chitosan research:

It is an amazing polysaccharide that is yet to find its full potential in this world. Many people are trying to find out different applications for this, but the purification process and variability in batches are the practical problems encountered by all. But through our research and study we have found out ways to eliminate these problems. Being in a public forum, i have restrictions to disclose those studies.

Though still not an expert on chitosan, you can shoot your queries through my email.

Thank You.


Many manufacturers of chitosan-containing weight loss preparations claim that it doesn't have any side effects - which apparently, is not true. The only safe thing to say seems to be this: supplements should be taken cautiously, especially when taking other medications.

Did anyone find out how much chitosan is in, say, an average serving of soft-shelled crab? What is the concentration needed to cause the anticoagulant effects?

You could have just eaten some raw parsley. One cup of raw parsley contains 1,230% of your daily value of vitamin K!

So, what if you're taking some antibiotic that also kills the bacteria in your gut, thus, reducing the body's main source of vitamin K? I remember being on antibiotics AND Coumadin at the same time. I wonder if I was also receiving vitamin K supplements.

Coumadin actually works in part by reducing the amount of available vitamin K in blood/tissues.

Yet another interesting note: vitamin K deficiencies are extremely rare because it's normally produced by the bacteria that live in our intestines

Another interesting note (maybe obvious by now): vitamin K deficiencies have been linked to bleeding disorders.

Interesting note: the "K" of vitamin K stands for "Koagulation" in German, and it is so named because it's essential for blood coagulation.

The article states, "please be careful while experimenting with chitosan, because it might initiate blood clots even in the presence of blood thinners."

Great – blood clots AND uncontrollable bleeding – chitosan lets you have both! Now THAT’S great marketing potential.

Where can I get these chitosan bandages? I see great marketing potential for chitosan in aftershave lotions – no more embarrassing bits of bloody toilet paper stuck to your face! (If the aftershave companies see this and make $$$$, I want a cut.)

Warfarin is the same thing as Coumadin? That's interesting, because Coumadin is derived from coumarin, which is derived from licorice.

I can't believe I just used something I learned from organic chemistry [shock]

Warfarin (Coumadin) can be reversed by taking vitamin K, so if you think about vitamin K as an inhibitor of Coumadin, then chitosan inhibits the inhibitor by binding all the vitamin K.

The question in my mind is how chitosan works as a pro-coagulant. I used to work in a lab, and we discussed a paper on platelets once, and boy are they weird. I'm guessing that the key point here is that chitosan acts as a pro-coagulant when applied topically because it's so sticky. But when it's in the blood it binds vitamin K, which is sort of a coumadin inhibitor. So confusing.

How is it that chitosan thins the blood if it's supposed to be a pro-coagulant???

I should add that supplements aren't regulated by the FDA anyway!

Ironically, chitosan is used medically as a PRO-coagulant, not an ANTI-coagulant. And it doesn't just have "possible biomedical uses," it has ACTUAL biomedical uses. (It was FDA-approved several years ago for use in bandages – see http://www.usmedicine.com/article.cfm?articleID=989&issueID=69

Conversely, chitosan is not FDA-approved for weight-loss purposes (although it is being marketed as a weight-loss supplement).

Michael, are you on blood thinners? If you're not, I don't think you should be concerned about eating a soft-shelled crabs :)


I guess this is quite controversial because I've read studies linking chitosan to weight gain and having possible hypercholosterolic properties. Chitosan sold for weight loss is sold as a dietary supplement, and therefore, does not have FDA approval. I'd have to warn anyone to take this only with extreme caution.

Janet, I'm not sure how effective it is, or what other uses there are, but chitosan has been used in diet pills as a "fat-fighting fiber" that supposedly reduces cholesterol and triglyceride blood plasma levels.

What is chitosan used for commercially?

I have the same question as Max: Does the chitosan increase bleeding since it makes the anticoagulant, warfarin work better? Leo also mentions clotting. Is this another property of chitosan? What factors are involved in how chitosan affects the blood?

So, if warfarin's anticoagulation effect is increased, does this mean that people have an increased risk of bleeding or clotting?

Doesn't warfarin interact with a lot of different medications? Does anyone know more about this?

To answer Michael's questions, I think it depends on how regularly you eat shellfish. If you do have a blood problem, I would certainly talk to your doctor. If you don't, I think you should be fine, as long as you heed the normal cautions associated with eating seafood, especially shellfish.


I would be interested in knowing more about your research. One thing that has always been of interest to me is the likelihood of basic science studies translating into clinical practice. Does your research show effects in humans? In vitro? In vivo? I have no doubt that these effects are real, but what is the clinical significance of this finding? Doses? Any help would be great.

Did the subjects in the study receive chitosan supplements, or did they just eat foods that contain chitosan? Soft shell crabs are one of my all-time favorite foods. I wonder if eating a soft shell crab dinner contains enough chitosan to cause these effects.

I am a researcher who is working on similar biopolymers. Let me warn you that the hemostatic (coagulation) properties of chitosan are proved and documented. So please be careful while experimenting with chitosan, because it might initiate blood clots even in the presence of blood thinners.

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