a question on amiodarone

[Guest guest]

I came across an acticle on amiodarone and it mentioned it's high

iodine content (37% by weight).

Should we be specifically asking about allergies to iodine and

shellfish when administering it in a non arrest situation? I haven't

seen anything about it and apparently it isn't mentioned in the PDR.

Inquiring minds want to know. Thanks

Eddie

[Guest guest]

Still need to ask, but shouldn't withhold.

Chris

PIC QUESTION OF THE WEEK: 11/21/05

Q: Is there a risk in using amiodarone in patients with iodine

hypersensitivity?

A: Amiodarone is a popular drug for the treatment of supraventricular

and ventricular arrhythmias. Each

200 mg tablet contains 75 mg (37.3%) of iodine. The product

literature includes a contraindication to its use in patients with

hypersensitivity to iodine. The question arises, what is iodine

hypersensitivity? Patients who report allergies to shellfish or

contrast media do not possess true sensitivity to iodine. Allergic

reactions to shellfish are usually the result of hypersensitivity to

tropomyosin, a protein found in the muscle tissue of shellfish and

mollusks. Allergic-like reactions caused by contrast media are

generally due to the high osmolarity or ionic nature of the dye. Most

of these reactions can be prevented by using a low-osmolality and/or

non-ionic compound. When a patient presents with a stated iodine

allergy, further investigation into the nature of the reaction is

suggested. Iodine hypersensitivity is difficult to define and not

well documented in the literature. Iododerma is a dermatologic

condition characterized by skin eruptions, sometimes described as

vegetating or ulcerative masses, often noted on the neck,

extremities, and trunk. The condition is usually associated with

excessive doses of iodine. A recent publication describes three

patients with a history of iodine hypersensitivity who were

subsequently challenged with amiodarone. Two of the cases involved

histories of reactions to contrast media while the third patient had

experienced shellfish sensitivity. There was little data in the

patient histories describing the individual reactions. These three

patients were administered amiodarone for chemical cardioversion of

various arrhythmias. There were no adverse events considered

secondary to the iodine present in the drug. It has been reported

that as many as 80% of patients experience adverse reactions with

amiodarone, but the associated dermatological reactions (rash, blue-

gray pigmentation, and photosensitivity) are not caused by iodine.

One author has suggested that the contraindication for using

amiodarone in patients with iodine allergy has generally been

disregarded. Evidence for avoiding amiodarone in patients with iodine

hypersensitivity is extremely limited and does not appear to support

its contraindication in patients with severe arrhythmias.

References:

• Brouse S, S. Amiodarone use in patients with documented

allergy to iodine-containing compounds. Pharmacotherapy 2005;25:429-

34.

• Allergy and Asthma Management Center: Ask the Expert:Drug Reaction.

http://www.aaaai.org/aadmc/ate/drugreaction.html (accessed 2005 Nov

16).

J. Kresconko, Pharmacy Clerkship Student Tara B. Creehan,

Pharmacy Clerkship Student

The PIC Question of the Week is a publication of the Pharmaceutical

Information Center, Mylan School of Pharmacy, Duquesne University,

Pittsburgh, PA 15221

>

> I came across an acticle on amiodarone and it mentioned it's high

> iodine content (37% by weight).

>

> Should we be specifically asking about allergies to iodine and

> shellfish when administering it in a non arrest situation? I

haven't

> seen anything about it and apparently it isn't mentioned in the PDR.

>

> Inquiring minds want to know. Thanks

>

> Eddie

>