Thursday, 17 July 2014

Why do some people have trouble doing things in moderation?

This is related to my previous post.

Some people take low-carbing to an extreme, 'cos if reducing carbohydrate intake has benefits, reducing it to zero must be better. Oy!

We're told that eating 5 portions of fruit and vegetables a day is good for us. One patient who was admitted to St George's with malnutrition, had been eating more than 50 portions of fruit and vegetables a day, 'cos if 5 portions of fruit and vegetables a day is good for us, 50 portions of fruit and vegetables a day must be better. Oy!

People who are taking the anti-clotting medication Warfarin need to maintain an accurate balance between their warfarin dose and their Vitamin K intake to keep their INR between 2 and 3, as warfarin antagonizes vitamin K1 recycling, depleting active vitamin K1.
"Between 2003 and 2004, the UK Committee on Safety of Medicines received several reports of increased INR and risk of haemorrhage in people taking warfarin and cranberry juice. Data establishing a causal relationship is still lacking, and a 2006 review found no cases of this interaction reported to the FDA; nevertheless, several authors have recommended that both doctors and patients be made aware of its possibility. The mechanism behind the interaction is still unclear." Here's a clue...

From Possible interaction between warfarin and cranberry juice (emphasis, mine):-
"After a chest infection (treated with cefalexin), a man in his 70s had a poor appetite for two weeks and ate next to nothing, taking only cranberry juice as well as his regular drugs (digoxin, phenytoin, and Warfarin). Six weeks after starting cranberry juice he had been admitted to hospital with an INR (international normalised ratio) > 50. Before, his control of INR had been stable. He died of a gastrointestinal and pericardial haemorrhage. He had not taken any over the counter preparations or herbal medicines, and he had been taking his drugs correctly." Cranberry juice contains no Vitamin K. Oy!

"The Committee on Safety of Medicines has received seven other reports through the yellow card reporting scheme about a possible interaction between warfarin and cranberry juice leading to changes in INR or bleeding. In four cases, the increase in INR or bleeding after patients had drunk cranberry juice was less dramatic. In two cases, INR was generally unstable, and in another case INR decreased. Limited information is available about whether patients complied with their treatment in these cases.

Cranberry juice (Vaccinium macrocarpon) is popular and is also used to prevent cystitis. Interaction with warfarin is biologically plausible, because cranberry juice contains antioxidants, including flavonoids, which are known to inhibit cytochrome P450 enzymes, and warfarin is predominantly metabolised by P450 CYP2C9. The constituents of different brands of cranberry juice may vary, and this might affect their potential for interacting with drugs. Whether the constituents of cranberry juice inhibit CYP2C9 and therefore the metabolism of warfarin or interact in another way needs further investigation. Until then, patients taking warfarin would be prudent to limit their intake of this drink." Oy!

So, one man's inadvertent (his doctor should have warned him about eating next to nothing while taking warfarin) dietary extremism resulted in his own death and the restricted intake of cranberry juice for everybody else taking warfarin. Oy. :-(

P.S. It's about time an alternative to warfarin was found. It's difficult to maintain an accurate balance between warfarin dose and Vitamin K intake.

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