Question:
I would like information on the possible effects of taking Imitrex when
one is allergic to Sulfa drugs (severe hives). An ARNP I worked with
told me there was a cross-sensitivity, and showed me the literature (I
had asked for a prescription, and she was explaining why she was not
comfortable prescribing it for me). My current Dr. says she's never
heard of this, and I could take it safely. I would be interested in
taking Imitrex if it was certain I wouldn't have hives or something
worse. Any information would be appreciated.
Answer:
Imitrex does contain a sulfur group, so you may get a reaction from
it. I get migraines myself and take Imitrex for them. It's the only
thing I've ever tried that was effective. It usually works for me
within 45 min. If I take Tylenol, Fiorinal, Midrin or another
analgesic, I don't stop vomiting long enough to keep them down. As
long as you don't have heart problems and hives are the worst you get
from sulfa drugs and nothing else works for you, I'd say it's worth
the risk of itchiness ( knowing the agony of migraines).Well, your ARNP was being a bit over cautious and your physician is (NO, is that
POSSIBLE?) uninformed about the drugs s(he) is prescribing. Perhaps your
pharmacist would have been able to resolve this question for you. This blip from MicroMedex sums up the controversy nicely:
SUMATRIPTAN (Imitrex(R)) is a serotonin agonist (5-HT(1D))
used to acutely abort migraine headaches. Confusion has arisen
concerning the risk of allergic reactions in patients with sulfa
allergies receiving sumatriptan since different sources contain
conflicting information. For example, the Pharmacist's Letter
recommends asking patients about sulfa allergies before
dispensing sumatriptan (Anon, 1995). In contrast, Facts and
Comparisons contains no such warning (Olin, 1995).
The compound responsible for a "sulfa" allergy to antibiotics is
a sulfonamide moiety attached to a benzene ring (Anon, 1995).
Although sumatriptan contains a sulfonamide, it is not attached
to a benzene ring. CROSS SENSITIVITY, therefore, is not
anticipated (Anon, 1995a). After receiving reports of adverse
effects (ranging from rashes to anaphylaxis) in patients with
known sulfa allergies, the manufacturer Glaxo-Cerenex cautiously
added a sulfa allergy precaution to the product labeling
worldwide in April, 1994 (Anon, 1995a; Pers Comm, 1995). The
FDA, however, reviewed the adverse reaction data and determined
that patients with known sulfa allergies were not at higher risk
for such events compared to other patients. As a result, the
sulfa allergy precaution was withdrawn from the product labeling
only in the United States in October, 1994 (Pers Comm, 1995).
Sumatriptan, therefore, is not contraindicated in patients with
known sulfa allergies. These patients should, however, be
followed for the development of HYPERSENSITIVITY.
