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From: dyer@spdcc.UUCP (Steve Dyer)
Newsgroups: net.med
Subject: Re: question about potassium supplements
Message-ID: <21@spdcc.UUCP>
Date: Fri, 28-Feb-86 01:40:55 EST
Article-I.D.: spdcc.21
Posted: Fri Feb 28 01:40:55 1986
Date-Received: Sat, 1-Mar-86 17:21:21 EST
References: <7@athena.UUCP>
Distribution: net
Organization: S.P. Dyer Computer Consulting, Cambridge MA
Lines: 43

In article <7@athena.UUCP>, glenm@athena.UUCP (Glen McCluskey) writes:
> The typical person is estimated to need a few thousand
> milligrams of potassium a day.  The largest supplements
> I have seen contain about 100 milligrams, I think due to
> the irritating effect potassium has on the stomach and
> intestines.  I have read various places that one should
> not take more than about one of these tables at a time.
> 
> Given this, is this form of supplement of any value, assuming
> that a person has a known deficiency?  It seems like the
> supplement is such a small percentage of the need that
> it is not worth it.

Most people who eat a balanced diet get all the potassium they need.
For those people who have a medically proven deficiency of potassium
which requires more agressive treatment than dietary means, supplements
providing sufficient amounts of the ion are available on prescription
in both liquid and tablet forms.  The liquid forms are generally thought
to be an acquired taste, and many people refuse liquid potassium therapy.
The older enteric-coated tablets of potassium were withdrawn from the market
because of the incidence of ulcerations of the GI tract.  The newer tablets
contain potassium salts in a wax matrix, leading to slower delivery of the
ion within the gut, with the intention of lowering the incidence of GI
irritation and ulceration.  Nevertheless, cases of ulceration have still
been reported with such preparations.

Potassium can have potent and possibly fatal effects on the heart
if taken to excess.  This is why, along with the aforementioned irritant
effects, potassium supplements in any physiologic dosage are limited
to being sold on a doctor's prescription.  Even with this, hyperkalemia
(excessive levels of K+ in the blood) is one of the most frequent causes
of iatrogenic (treatment-induced) morbidity and mortality in the US
(it isn't even easy for doctors to get it right!)  Potassium deficiency
is very very rare unless one is being treated with certain diuretics
like thiazides.  Even that can be tricky, because some non-thiazide diuretics
actually conserve K+, meaning that adding extra K+ through supplements
is asking for trouble.  Of course, any reputable doctor wouldn't combine
the two, but often such patients are being treated by several doctors,
and the pharmacist may or may not catch such instances of polypharmacy.
-- 
Steve Dyer
dyer@harvard.HARVARD.EDU
{bbncca,bbnccv,harvard}!spdcc!dyer