Re: KI Pills & the Incidence of Untoward Effects

[mozley@darius.pet.upenn.edu (P. David Mozley, M.D.)]

>          Regarding the use of KI pills, Mozley writes: "The risk of
>          anaphylaxis to KI is low, but the consequences for any occurence
>          are potentially catastrophic . . .

This risk was considered in NCRP Report 55, Protection of the
>          Thyroid Gland in the Event of Releases of Radioiodine."  Section
>          4.5.  Using data provided from pharmaceutical manufacturers
>          (therapeutic doses of iodide manufactured per year) and the
>          incidents of adverse drug reaction rate reported to FDA, the NCRP
>          estimates the rate of adverse reaction for 300-mg doses
>          therapeutic doses of iodide to be 5E-7/y.

In my practice, the incidence of untoward effects from the administration
of SSKI is substantially higher than the rate REPORTED TO THE FDA.  Two of
my patients with severe skin reactions have required aggressive management
after a single dose before an MIBG study.  Severe sialadenitis has been
seen even more commonly in a variety of settings.  The iodide load may have
contributed to the death of another patient, who was, albeit, already very
sick, and died of acute pulmonary edema about 8 hours after administration.
Et cetera, et cetera, ad nauseum.  Speaking of which, the most common
problem, nausea and vomiting, can become a serious problem for some cardiac
and hypertensive patients.  We prescribe SSKI to increase airway secretions
in kids.  These pharmacological benefits in children could be risky in a
number of adult patients.  So administration of SSKI requires knowing the
risks and making a formal assessment that the potential benefits for a
given individual outweigh the risks for that individual.  That assessment
is challenging to make unless you actually see the patient, take a history,
and perform a physical exam.  So most physicians will be reluctant to
prescribe a potentially potent medicine to a large population of patients
that they have not examined.

>          NCRP also makes one other important point concerning adverse
>          effects:

>          "Although there are many individual reports of complications of
>          iodide administration in medical literature, these are anecdotal
>          in that they list a number of cases with the complications, but
>          do not give the number of patients taking iodides from which the
>          cases demonstrating abnormalities are drawn."

A point well taken.  Efforts to track the incidence of untoward effects in
a more rigorous way should be increased.  All I can share with you that
might be constructive is the idea that the actual incidence of some
problems is not always  relevant to the practice of medicine.  A single
anecdote is sometimes enough to influence your management.  If you have
ever induced anaphylaxis in one of your patients and sweated bullets until
they recovered, then you tend to act like every patient could be the next
victim, regardless of whether the risk is really very low.  You do not want
your own blood pressure going through the roof again as your patient's
falls through the basement, so you tend to not do again whatever it was
that you did unless it's really indicated.

In synopsis, SSKI is not always a benign drug.  I have seen it hurt people.
My experience is only anecdotal, but it's all I have on which to base my
professional behavior.  So I recommend caution when prescribing it.

Hope this helps.

mozley@darius.pet.upenn.edu