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Potassiuim Iodide
Tablets
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Phone
(310) 457-1775
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Facsimile
(310) 589-1926
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Email
Address
info@pacifichealth.com
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Mailing
Address
Pacific Health Sciences
PO Box 6828
Malibu, CA. 90264
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| Potassium Iodide
as a Thyroid Blocking Agent in Radiation Emergencies
Meets FDA guidelines
(Dec., 2001)
300,000 doses of RAD BLOCK potassium iodide
were recently purchased by Health and Human Services
(HHS).
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Protects Thyroid From Radioiodine
Poisoning
Downwind from a
nuclear accident or detonation, most casualties result from radioactive iodine
poisoning of the thyroid gland. Children are the highest risk group. Potassium
iodide, if taken before exposure, reduces the threat by 95%.
Potassium
Iodide as a Thyroid Blocking Agent in Radiation
Emergencies
Recommended Doses of Potassium Iodide for Different Risk
Groups
| |
Daily
potassium iodide dose (mg) |
# of 65mg
Tablets |
| Adults over
40 yrs |
130 mg |
2 |
| Adults over
18 through 40 yrs |
130 mg |
2 |
| Pregnant or
lactating women |
130 mg |
2 |
| Adoles. over
12 through 18 yrs* |
65 mg |
1 |
| Children
over 3 through 12 yrs |
65 mg |
1 |
| Over 1 month
through 3 years |
32 mg |
1/2 |
| Birth
through 1 month |
16 mg |
1/4 |
*Adolescents
approaching adult size (> 70 kg) should receive the full adult dose (130
mg).
The protective effect of potassium iodide lasts approximately 24
hours. For optimal prophylaxis, potassium iodide should therefore be dosed
daily, until a risk of significant exposure to radioiodines by either
inhalation or ingestion no longer exists. Individuals intolerant of potassium
iodide at protective doses, and neonates, pregnant and lactating women (in whom
repeat administration of potassium iodide raises particular safety issues, see
below) should be given priority with regard to other protective measures (i.e.,
sheltering, evacuation, and control of the food supply).
Note that
adults over 40 need take potassium iodide only in the case of a projected large
internal radiation dose to the thyroid (>500 cGy) to prevent
hypothyroidism.
These recommendations are meant to provide states and
local authorities as well as other agencies with the best current guidance on
safe and effective use of potassium iodide to reduce thyroidal radioiodine
exposure and thus the risk of thyroid cancer. FDA recognizes that, in the event
of an emergency, some or all of the specific dosing recommendations may be very
difficult to carry out given their complexity and the logistics of
implementation of a program of potassium iodide distribution. The
recommendations should therefore be interpreted with flexibility as necessary
to allow optimally effective and safe dosing given the exigencies of any
particular emergency situation. In this context, we offer the following
critical general guidance: across populations at risk for radioiodine exposure,
the overall benefits of potassium iodide far exceed the risks of overdosing,
especially in children, though we continue to emphasize particular attention to
dose in infants.
Why do I need potassium iodide
?
1. Radioactive iodine (predominantly Iodine-131) is a major
radioisotope constituent in nuclear power plants.
2. Radioactive
iodine (predominantly Iodine-131) is also a major constituent of detonated
nuclear weapons.
3. After a nuclear incident, a majority of DOWNWIND
casualties that result are attributed to thyroid cancer.
4.
Radioactive iodine (radioiodine) persists in the environment for a month or
more.
5. Excess iodine in the blood (either radioiodine or stable
Iodine), is quickly eliminated from the body, but only after the thyroid has
become saturated with one or the other type of iodine.
6. Even very
small amounts of radioactive iodine, because it is retained in the small space
of the thyroid, eventually will give such a large radiation dose to thyroid
cells there that abnormalities are likely to result.
7. The most
likely to see the worst effects, in later life, are the youngest children. 8.
The present threat of nuclear terrorism, including nuclear reactor threats and
dirty nukes (simple radiologically-enhanced conventional
explosives).
How does potassium iodide protect me ?
The
recently updated (1999) World Health Organization (WHO) Guidelines for Iodine
Prophylaxis following Nuclear Accidents states:
"Stable iodine administered before, or promptly after,
intake of radioactive iodine can block or reduce the accumulation of
radioactive iodine in the thyroid." The Nuclear Regulatory Commission (NRC)
stated July 1, 1998 in USE OF POTASSIUM IODIDE IN EMERGENCY
RESPONSE:
"Potassium iodide, if
taken in time, blocks the thyroid gland's uptake of radioactive iodine and thus
could help prevent thyroid cancers and other diseases that might otherwise be
caused by exposure to airborne radioactive iodine that could be dispersed in a
nuclear accident." National Council on Radiation Protection and Measurements.
NCRP Report NO. 55. Protection of the Thyroid Gland in the Event of Releases of
Radioiodine. August, 1979, Page 32:
"A major protective action to be considered after a serious accident
at a nuclear power facility involving the release of radioiodine is the use of
stable iodide as a thyroid blocking agent to prevent thyroid uptake of
radioiodines.
" Federal Register.
Vol. 43 Friday, December 15, 1978, states in Potassium Iodide as a Thyroid
Blocking Agent in a Radiation Emergency:
"Almost complete (greater than 90%) blocking of peak radioactive
iodine uptake by the thyroid gland can be obtained by the oral administration
of ... iodide ...
" National Council
on Radiation Protection and Measurements. NCRP Report NO. 55. Protection of the
Thyroid Gland in the Event of Releases of Radioiodine. August, 1979, Page
32:
"A major protective action to be
considered after a serious accident at a nuclear power facility involving the
release of radioiodine is the use of stable iodide as a thyroid blocking agent
to prevent thyroid uptake of radioiodines.
" The Nuclear Regulatory Commission (NRC) states in COMSECY-98-016 -
Federal Register Notice on Potassium Iodide:
"In 1978, the U.S. Food and Drug Administration found potassium
iodide"safe and effective" for use in radiological emergencies and approved its
over-the-counter sale." Recall Three
Mile Island and Chernobyl. To be effective, potassium iodide must be taken
prior to radioiodine exposure. If a nuclear terrorist incident occurs, will you
and your family be waiting in line to get it from the government? THINK AHEAD.
Following the last several nuclear accidents, Potassium Iodide was literally
impossible to purchase.
When
should I take potassium iodide?
The FDA potassium iodide product insert says:
"Potassium
iodide should be taken as soon as possible after public health officials tell
you. You should take one dose every 24 hours.
" Also, from the Health
Physics Journal, Volume 78 No. 6, June 2000, "EFFECTS OF TIME OF ADMINISTRATION
AND DIETARY IODINE LEVELS ON POTASSIUM IODIDE (KI) BLOCKADE OF THYROID
IRRADIATION BY 131-I FROM RADIOACTIVE FALLOUT" Pat B. Zanzonico and David V.
Becker
(Read abstract by searching
title at Health Physics Journal): "KI administered up to 48 hours before 131-I
exposure can almost completely block thyroid uptake and therefore greatly
reduce the thyroid absorbed dose. However, KI administration 96 hours or more
before 131-I exposure has no significant protective effect. In contrast, KI
administration after exposure to radioiodine induces a smaller and rapidly
decreasing blockade effect. KI administration 16 hours or
later.
Updated June 26, 2002 |
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