Re: Potassium Iodide -Reply -Reply -Reply

[Charles Willis <CAW@nrc.gov>]

Dr. Rozental,

You certainly are on target with reference to the WHO Manual.  Unfortunately, the
problem is not that simple.  In May 1998, the WHO issued a draft revision of their
recommendations with significant changes.  Evidently, the WHO realized that the
NCRP risk estimates for KI were several orders of magnitude low.  The use of KI
continues to be recommended but with several caveats such as do not give KI to
people who: are allergic to iodine, have ever had thyroid disease of any kind,  or
have dermatitis herpetiformis.  The WHO also advises the variation of KI intake
with age, ranging from 100 mg for adults to no more than 12.5 mg for neonates. 
The WHO also advises against the use of KI in the ingestion phase, even though
almost all the thyroid cancer attributed to Chernobyl occurred outside the plume
emergency preparedness zone.

In addition to the WHO warning, medical references such as the Physician's Desk
Reference say the KI should not be given to people who are taking certain
medications, such as those containing lithium or potassium, and that taking KI
concurrent with a potassium-sparing diuretic can lead to cardiac arrest.  

Then there are the practical difficulties of actually administering KI in a timely
manner, preferably shortly before the inhalation of the radioactive iodine.  

Enough said; it is a tricky problem.

Charlie Willis
caw@nrc.gov