Narcotics
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þ Narcotic Allergy

> Many patients claim codeine allergy, but really just have intolerance
> from GI/CNS side-effects. However, an occassional patient appears to
> have a true history of rash, and maybe even anaphylaxis. I have always
> written these people to get either oxycodone or hydrocodone. I have
> never been told of a reaction nor have I ever even been questioned by a
> pharmacist until just the other day. What do others on the list feel
> about oxycodone or hydrocodone for a patient who claims a true allergy
> to codeine?


As I'm sure you already know (but for the benefit of others  ;)) true
allergy to optiates although occasionally described (1,2) is very rare.
Most urticarial, bronchospastic and hypotensive reactions to opiates are
due to direct mast cell degranulation in the same manner as that caused
by nonsteroidals and iodinated contrast media.  These reactions can be
prevented by H1 (and H2) blockers and result from direct histmine release
and not IgE mediated allergy.  Opiates that have no histimine releasing
properties such as fentanyl do not have this drawback.  Nevertheless
hypotension may occur via a depression of the medullary vasomotor center
with larger doses.  It may well be that true allergy to morphine and
codeine is dependent upon a shared chemical structure (-OH group at
position 6) (2).  Both hydrocodone and oxycodone have a =O group at this
position and thus, theoretically do not cross react.

In practice it is very common to see uritcaria from the administration of
morphine.  We see it occasionally in sicklers.  Our (written) policy is to
administer it nonetheless (unless an anaphylactic reaction has previously
occured) but pre-treat with benedryl. We do this all of the time but
still ocassionally see breakthrough urticaria which is easily managed. I
would refrain from doing this if bronchospasm has previously occured or
anything more significant than an immediate wheal and flare reaction is
described, but I have yet to encounter any.


H. Louzon MD


(1)

de Groot AC, Conemans J
Allergic urticarial rash from oral codeine [published erratum appears in
Contact Dermatitis 1986 Sep;15(3):194]
Contact Dermatitis 1986 Apr;14(4):209-14

A case of an urticarial rash from delayed-type allergy to orally
administered codeine is presented. The literature on contact allergy to
codeine is reviewed, and the r"ole of patch testing in drug eruptions
discussed.

(2)


Voorhorst R, Sparreboom S
Four cases of recurrent pseudo-scarlet fever caused by phenathrene alkaloids
with a 6-hydroxy group (codeine and morphine).
Ann Allergy 1980 Feb;44(2):116-20

Four patients with a clinical picture resembling that of scarlatina are
described. This clinical picture was found to be based on a delayed-type
allergy for codeine and morphine. Investigation showed that the codeine or
morphine allergy is essentially dependent on the hydroxyl group at the 6
position of the basic phenanthrene structure but only when this group is
bound equatorially, as is the case for codeine and morphine.