Fluid Intake after RAI (was Newbie with question on RAI)

May 4, 2001

Beth Sargent wrote:

> ....(snip).....I went

> into the hospital they gave me the I131 (RAI) and shut

> the door. I was told to drink a lot of water so I

> would go the bathroom a lot. I did that couldn't

> sleep so I drank water, went the bathroom and watched

> tv I was home after 23 hours.

It is fairly typical for hospital personnel to give the instructions to

'drink lots of water to flush out the RAI so you can go home quickly'.

Unfortunately this is not a good idea. Please see Dr. Ain's post below.

Marilyn (dx '94-pap w/lung metastases - 5 pos scans/435mCi's - scans 6 &

7 clean)

* * * From Dr. Ain * * *

Dear ThyCa Members: (REPOST)

Concerning fluid intake during I-131 therapies:

I typically advise patients (after doses < 250 mCi) to drink

only when thirsty. Attempts to " wash out " the radioiodine are

self-defeating, particularly in the first 48 hours. This is because,

a significant portion of the effective radioiodine recirculates for

additional therapeutic uptake into remnant or tumor tissue. Drinking

large quantities of liquid to cause a forced diuresis actually lowers

the effectiveness of the administered radioiodine.

After doses exceeding 250 mCi, it is advisable to drink 8 oz

of liquid each waking hour and to empty the bladder every two hours,

only for the first day. This is calculated to minimize radiation

dose to the bladder wall and ovaries. Drinking more, or less, actually

increases the radiation dose to these organs. After the first day,

drink

when thirsty and urinate when you want. It is quite rare for patients

to

require more than 48 hours hospitalization after radioiodine doses

under 200 mCi, unless they have kidney problems. Our own protocol is

to discharge patients (with normal kidney function) after 24 hours

for I-131 doses less than 500 mCi.

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