I think I really need to stop stalking the internet for information about
SVT and medications...seriously, lately I'm finding more and more information that literally scares me to death. My most recent finding is an article about
Amiodarone. I found it while trying to figure out what a skin rash caused by Amiodarone looks like. As I've
posted before Miss K has a chronic case of
Eczema but a few weeks ago she had a breakout on her chin that turned into an infection. After a visit to the
Pediatrician I was not too concerned about it, especially after it cleared up within days with an
antibiotic cream and
Hydrocortizone. This week she developed the same rash on her right elbow and it is now showing up on her left forearm and elbow as well. I immediately started applying Hydrocortizone to the areas but it still has ended up looking like her chin did so I've started applying the antibiotic as well. I'm not sure if I need to be concerned or not, I'm guessing it may be the sunscreen we are using that could be causing these rashes so I have stopped using it and switched to another and I hope it works. Otherwise I am afraid she's starting to have a reaction to the Amiodarone, but in the back of my mind I can't help but think that the rash wouldn't go away with an antibiotic cream if that were the case, or would it???? So today I started researching again and found this article, there wasn't anything helpful about skin rashes but it was enough to terrify me about other
side effects, seriously what am I giving my poor little girl?
Source:
http://heartdisease.about.com/library/weekly/mcurrent.htm
The
strange life of amiodarone
Amiodarone is the most
effective, and certainly the strangest, antiarrhythmic drug ever developed.
(Antiarrhythmic drugs are used to treat heart rhythm disturbances. Click
here for a quick review of heart rhythm
disturbances.) Anyone being treated with amiodarone should understand
the idiosyncrasies - and the risks - associated with this highly effective drug.
The strange history of
amiodarone in the U.S.
Amiodarone was developed in
Belgium in the 1960s as a drug for treating angina, and was quickly released for
marketing in most countries except the United States. Doctors noticed
that, in their patients placed on amiodarone, heart arrhythmias greatly
diminished. Clinicians quickly began using the drug to treat cardiac
arrhythmias of all sorts. Within a few years, word began filtering into
the United States - amiodarone was a unique antiarrhythmic drug that was said to
"always work, and had no side effects." Both of these assertions, of
course, proved false.
In the late 1970s, American
doctors began obtaining amiodarone from Canada and Europe to use in their
patients with life-threatening arrhythmias who did not respond to any other
drugs. The FDA sanctioned this activity on a limited basis, but the drug
seemed so effective that literally hundreds of American electrophysiologists
were soon obtaining the drug (one way or another) and by the mid 1980's tens of
thousands of Americans were receiving the drug. The Americans, as a group,
studied the effects of amiodarone somewhat more rigorously than their overseas
colleages, and here's what they found: Amiodarone was indeed far more effective
at suppressing arrhythmias than any other drug they had ever seen, but it
produces a bizarre series of side effects that doctors around the world seemed
to have "missed." By the mid 1980s, the FDA was essentially forced to
release amiodarone for marketing in the U.S. - the foreign manufacturers of the
drug threatened to cut off the American supply (having supplied free drug to
thousands and thousands of Americans for more than 5 years,) and the American
doctors impressed on the FDA what a medical disaster that would produce.
So, unlike any other drug in modern history, amiodarone became FDA approved
without rigorous, FDA-approved randomized clinical trials. The true
breadth of amiodarone-induced side effects took more than a decade to uncover.
Why amiodarone is a
strange drug
Amiodarone has several
characteristics that make it unique.
First, the drug takes weeks
to achieve its maximum effectiveness. This is because amiodarone is stored
in most of the tissues of the body, and to "load" the body with the drug, all
the tissues need to be saturated. The typical "loading" regimen of
amiodarone, therefore, is to use very large doses for a week or two, then taper
the dosage over the next month or so. It is not unusual to give patients
1200 or 1600 mg per day at first, and then maintain them on as little as 100 or
200 mg per day chronically.
Second, amiodarone leaves the
body very, very slowly. It is not excreted (like most drugs) by the
liver or the kidneys. It is lost when amiodarone-containing human cells
are lost - such as skin cells or cells from the GI tract, which are shed by the
millions each day. Thus, if it is decided that one needs to stop
amiodarone, the drug remains in the body in measurable quantities for months and
months. The "half life" of the drug, in contrast to most other drugs, is
measured in weeks instead of hours.
Third, because amiodarone is
stored in many different kinds of tissues, it can produce side effects affecting
many different organs. Some of these side effects take months or years to
develop, so it is never true that one can stop being vigilant.
Fourth, amiodarone works
through many different mechanisms, unlike most drugs. It fits into two
separate categories of antiarrhythmic drugs (Class I and Class III, for what
it's worth); it acts as a beta blocker; it acts as a calcium blocker; it acts to
dilate blood vessels; and it often acts to "block" the effect of thyroid
horomone.
The strange side effects
of amiodarone
One reason the side effects
of amiodarone were not spotted for years was that they often take weeks or
months to develop (unlike side effects from typical antiarrhythmic drugs, that
usually appear within days). Also, the kinds of side effects produced by
amiodarone are not the kind that heart doctors typically expect with
antiarrhythmic drugs. In any case, it took more than a decade for many European
doctors to admit (even after the American medical literature became saturated with
articles) that they had been missing some rather remarkable side effects.
Amiodarone commonly causes
deposits to form on the cornea of the eyes - in fact, this occurs in virtually
every one taking the drug. These deposits often cause no visual
disturbances, but not infrequently patients complain of "halo-vision," where
looking at bright lights at night is like looking at the moon on a foggy
evening.
Amiodarone can cause a very
disfiguring blue-grey discoloration of the skin, generally in areas of sun
exposure, and that gradually worsens over a period of years. It is not
clear that this "smurf syndrome" clears up when the drug is stopped.
In younger patients this side effect can be devastating.
Amiodarone often sensitizes
the skin to sunlight, so that even trivial exposure can cause a fairly nasty
sunburn. People taking amiodarone must often cover the body completely
when going out during the summer, especially in hot, humid climates.
Each amiodarone molecule
contains four iodine atoms - so a typical dose of amiodarone provides far more
iodine to the body than is needed. It is thought to be the iodine that
mediates the thyroid side effects of amiodarone. The more common of these
is hypothyroidism - low thyroid. This, fortunately, is relatively easy to
treat with thyroid medication. But some patients develop hyperthyroidism -
high thyroid - and this can be a real problem and a real challenge to treat. (They
hyperthyroidism often does not respond to the "typical" treatment used for this
problem.)
Amidoarone can cause liver
toxicity, so liver enzymes need to be monitored periodically.
The most serious side effect
of amiodarone is pulmonary toxicity - lung disease. This comes in two
flavors. Amiodarone can produce an acute pulmonary syndrome that looks and
acts just like typical pneumonia - sudden onset of cough and shortness of
breath. This condition usually improves rapidly once amiodarone is
stopped. It can occur within days of beginning amiodarone. The
second flavor is more insidious - it is a gradual, unnoticeable, "stiffening" of
the lungs that both the doctor and patient can overlook until finally severe,
probably irreversible lung damage is done. This problem can occur years
after the drug is begun, or as early as a few months after beginning amiodarone.
When should amiodarone be
used?
If Satan were going to
develop an antiarrhythmic drug, he would make one that suppressed arrhythmias
very well (so people would want to use it,) had none of the typical side
effects, but that had a host of atypical, relatively subtle, but ultimately
dangerous side effects that doctors were likely to overlook. He might not
be satisfied with amiodarone, but would likely consider it a pretty good first
approximation.
Amiodarone should be used for
arrhythmias that are life-threatening or that are very disruptive to one's life,
and for which there are no other reasonable therapies. Despite its
drawbacks the drug has helped
tens of thousands of patients, and has restored them to a nearly normal life.
When used appropriately, amiodarone can be a major benefit.
But because of the potential
toxicity its use should be limited. No doctor should blithely prescribe
the drug, but should do so with reluctance, realizing that he/she is exposing
the patient to long-term risks. The doctor should, by prescribing the
drug, be committing him/herself to being a long-term partner of the patient.
He/she should carefully coach the patient on what problems to look for, and
together they should be ever vigilant for the side effects of the drug.
