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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
Avatar universal

92903 tn?1309908311
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)
Avatar universal
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
Avatar universal
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?
Avatar universal
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."

Avatar universal
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.
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