Ribavirin absorption-fats and PURINEs?!?!?!?

[merryBe]

Been working on my ideal strategy for next round of tx. and came across this little study of how high purine foods lower Riba absorption.
Since all we've ever discussed in here is how FAT helps riba to absorb,
I thought knowing what might hinder it's absorption was worth knowing also.

Ribavirin is found to be absorbed in the intestine through the human concentrative nucleoside transporter 2 (hCNT2). Cellular uptake of ribavirin was strongly inhibited by purine nucleoside in an in vitro study. This study aims to examine the effects of dietary purine on the pharmacokinetics of orally administered ribavirin in vivo. Twenty healthy participants were enrolled in a randomized, 2-period crossover study. Participants were administered a single 600-mg oral dose of ribavirin after either a high-purine meal or a low-purine meal. Serial blood samples were collected predose and over 144 hours after dosing. Ribavirin concentrations were measured by liquid chromatography/tandem mass spectrometry. In comparison with corresponding plasma values of ribavirin following a high-purine meal, Cmax, AUC0-144 and AUC0-∞ of ribavirin following a low-purine meal were 136% (90% confidence internal [CI]: 120%-155%), 134% (90% CI: 118%-153%), and 139% (90% CI: 120%-159%), respectively. This study indicates that dietary purines have an effect on ribavirin absorption. Dosage regimens of ribavirin might need to be adjusted according to the purine content of the meal.

SO I guess we can kiss our meat, fish and legumes goodbye....or at the very least limit them, as HR once suggested purely for liver health.

Now those treating have extra incentive to limit thier intake, or to at least plan their high protein meal to be at a different time than when they ingest their Ribavirin.

Discussion is welcomed.

mb

[eureka254]

Purines won't work but Murine might ;).

[child24angel]

My eyes hurt, they are not merry at all.

[viaduk]

----"is it better to clutch at straws or drown hoping for help?". Not much of a choice, but arguing about it helps pass the time while treading water. -----

Nice!!!

[willing]

you've hit on one of the main sources of disagreement around here - which can be restated as "is it better to clutch at straws or drown hoping for help?". Not much of a choice, but arguing about it helps pass the time while treading water.

There is *never* unequivocal evidence-based support for  alternative strategies : predosing, tapering, increasing dosage or duration, supplements, anti-fibrotics, etc.etc. If one is lucky there are one or two peer-reviewed studies that at least add plausibility.  For example SAMe and rbv predosing are both in the fairly credible category:  there is  a plausible mechansim and some attempts at validating the benefit but nothing yet unequivocally demonstrating clear benefit. Further out, for example with anti-fibrotics, the evidence gets much skimpier.

It's  easy to ridicule and dismiss the alternative approaches as unfounded wishful thinking. However  the alternatives only come up because the alternative to the alternatives is dismal. I sure hope people keep searching ...

[Trish77]

I understood your point, which is why my comment started out with…"this is totally aside…"  :)

Noted on the benefits of EVR, which is why I'd personally choose to add SAMe if I were treating again, despite the lack of corelation *at this time* to an increase in SVR rates among the SAMe group.  I'd take whatever edge I can get within reason and EVR is desirable.

Like you, I've got a bit of a time constraint at the moment (never mind posting when I shouldn't be) and I apologize as I usually like to post the data I'm referring to.  I'll get to it when I'm somewhere it's available to me, which it isn't at the moment. :)  

Thanks for your response, Susan.  

[Susan_1a_CC]

From: http://www.thebody.com/content/art46371.html

"(Early Virological Response): EVR means that hepatitis C viral load has dropped by 99% (2 logs), or is undetectable after 12 weeks of HCV treatment. An EVR is a good predictor of the ultimate response to HCV treatment. If a person does not have an EVR, their chance of SVR is very low (1-4%). Usually, HCV treatment is discontinued in people who do not have an EVR."

See how easy it is to imply a leap that's not exactly so.  Yes, I said increased SVR rates - and it's actually increased chance of SVR.  My point is in using prudence before implying the answer to an equation.  I'll be happy to post other info re your request when I have a few more minutes but it you yourself have already written "While I've seen data that shows SAMe contributes to early viral load drop" perhaps you'll make your own deduction given that EVR is related to SVR.  HTH.