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# How to calculate weight based Riba dose?

A couple of posts below, someone asked how to calculate weight based Riba.  A lot of recent posts state that it is important and most of us don't know how to figure out if we're on a high, low, or whatever level of Riba.

Can someone provide the formula (for pounds and for kilograms)?

JmJm once calculated mine.  Thanks.
39 Responses
See:

http://hepatitis-central.com/mt/archives/2004/12/weightbased_tre.html
For weight based dosing, the typical ranges are between 13.3 and 15.5 or so mg per kg of body weight. Generally, I think you want to be over 15. Divide your weight in lbs by 2.2 to get kg.

165/2.2 = 75kg
75kg X 15.5 = 1,162.5 mg

or supposing you were taking 800 mg for 165 lbs:

165/2.2 = 75kg
800kg/75kg = 10.6 (quite a bit outside of our 13.3 - 15.5 range)
That is really scary as I am pretty fat at 216lbs. I am only taking 800 riba a day...should I speak to doc about that? How about 180 Pegasys? Im only 5'1" (round lil porker since my 30's..lol)and also, I have heard that fat folks don't respond to tx as well...IS THAT TRUE???? Freakin' out now again...mkeela
Yes that is true about weight hindering SVR a bit. And yes if I was you I would definatey talk to your doctor about that riba amount ask him what he is basing the dosage on?
very good post, this is also of interest to me as my doc wrote the rx for 800mg of riba and i weigh 200lbs. some have said this seems low for me? i should be starting tx soon but i think i need to ask the doc to up the riba before i start. he is the top hep doc at a university hosp so not sure what his intentions are. maybe he is doing something like what is written below from dr bennet cecil?

"Ribavirin does not make the intererferon work, but it reduces the chance of relapse after treatment is completed. I start with 600 mg per day in most patients. Patients with genotype 2 or 3 will usually take 800 mg per day after the first month. Patients with other genotypes will usually gradually go up to 1,000 or 1,200 mg per day. If you raise the dose too quickly, the red blood cell count will fall too low causing anemia, fatigue and shortness of breath. If the patient is not responding I usually stop treatment. If you cure the infection, the liver will heal itself."

Im 3a and relapsed on 800 a day ( I weighed 185 at the time, Im just shy of 6 foot), so did FLGuy I believe. No way would I let him keep me at 800 riba a day THIS round! First time I was tx naive so I folowed instruction ike a good patient and the Tx failed.
I opted to take the mfg recommended dosage because it gave me 200 MORE mgs.  I was only supposed to get 800 on weight based.

I'm glad I did it though for my weight it caused big anemia problems...I made it through and did keep the extra riba on board the whole time.

ok flguy. spare the riba spoil the tx? My doc reduced my dosage from 1200mg to 1000mg 6 days ago. my hmg is down to 9.8 and i've got an appointment on the 23rd to discuss referral to a hematologist/procrit options. (no insurance. can get free meds but ouch the dr's visits!) my weight has dropped so the reduction is weight-appropriate. i'm in week 25/48. und @ 12 and 24 from pre-tx VL of 10million. anemia is kicking my a\$\$ so i was happy to reduce THEN. now, 6 days later, i'm worried i've increased my chance of relapse. am i freakin' for nothing? my GI doesn't seem to as "up" on things as some. his standard response is the first 12 weeks is the most important. did i just mess up my chances of svr? thanks you guys.
Kalio my BMI is 26.1. i was hoping jmjm would give me his opinion on starting a lower dose of riba and working it up to 1200 or more. since i have read that the peg is what does most of the work and riba just compliments and helps from relapsing. it seems that the riba does the worst damage (red count, etc) in the begining and then during tx. so why would taking 800mg to start then working up to 1200-1600 not work? perhaps not to shock your system as much. has there ever been any studies done on doing tx this way? the one doc that i posted the article from treats this way and has had great success. i'm not saying my doc treats this way or i would ever tx this way but i just wanted to ask out of curiosity. thanks in advance
Ditto what Kalio said.  About the same at start 185 lbs. Although I'll never know, part of the relapse cuprit was the fixed dose of 800 instead of about 1200 I think.  Better to suffer the anemia and be aggresive with procrit and other rescuse med.  I think it was Ben Franklin who say 'Spare the Riba, spoil the tx'.
Tritto what FLguy says. I'm 3a, started at 170 lbs and 1,200 riba. Paid the price with hgb in the 7's and 8's, but glad to have done it as I wait for my 6 mos post TMA. I was unD from 4 week into tx, through 4 and 12 weeks post. Still slinging chicken bones and goat entrails in the backyard every full moon.

Also, for those getting ready to start, note the short tx protocols for 2's and 3's. They use weight based dosing. There was also a study published no too long ago tht favorably compared higher weight based riba dosing to lower WB riba dosing.

And like Beagle says, always grab a handful of nuts when you take you're riba. (Single gals may find that challenging)
DC
Auburn, WA
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