Although I would agree that one should not give a pill or liquid to someone with a swollen airway, anaphylaxis can occur without airway involvement. More importantly, however, I don’t believe that training to inject an antihistamine is necessary or worthwhile.  The treatment for anaphylaxis is epinephrine, period.  If you had nothing else, that would be okay.  Except for hives, antihistamines do little for the acute symptoms.  In fact, no one has clearly demonstrated that they are even necessary.  We use them in the hope that they will decrease the likelihood of a biphasic or rebound reaction.

Q: We are moving from epi auto injectors to epi vials and I am working on updating our protocol.  Do you have a protocol for vials?

The protocol for treatment would be the same except for the actual steps of drawing up the medication.  You might want to consider a policy that addresses purchase, storage, disposal, training (I would refresh yearly), monitoring for expiration dates, and usage review (all allergic reactions whether or not meds were used).  With vials, I would suggesting adding that each should be discarded after being used for an episode of anaphylaxis (however many are needed for the episode).  With amps, I would use each for one injection.  In both cases, medication will be wasted but you will decrease the likelihood of contamination.  Given the relative costs compared to autoinjectors, they still remain very cost effective.

Click here to access the Wilderness Medical Associates’ Field Protocols, including Protocol 1: Anaphylaxis.

A: Interesting story. One can develop an allergic reaction to any medication or any of its ingredients. Antihistamine is a class of medications and there are a number of different ones that fall under that rubric. Diphenhydramine (e.g., Benadryl) is one. They can be used to treat allergic symptoms like hives and dampen or prevent them. Because drowsiness is a frequent diphenhydramine side effect, it is a commonly added ingredient in over-the-counter sleep aides in North America. It is not a naturally occurring hormone in our bodies so if this was indeed an immediate allergic/anaphylactic reaction, it or a chemical used during manufacture could have been the precipitant. Using the assumption that this was indeed an allergic reaction, the person could be allergic to any medication within the class. This could also have been an anticholinergic reaction to the diphenhydramine (e.g., flushed skin, dry mouth, anxiety, urine retention, constipation) or an anaphylactic reaction to something else the person was exposed to. True allergic reactions to antihistamines are unusual. Fortunately we have other better options for serious reactions (e.g., epinephrine, corticosteroids).

What about allergic reactions to epinephrine? Epinephrine is produced by the body endogenously. Most supposed allergic reactions are in fact caused by adrenergic side effects (e.g., rapid heart rate, shakes, vasoconstriction). Other reactions attributed to epinephrine may be caused by the xylocaine (anaesthetic) it is mixed with for local dental anaesthesia. Conceivably, a true allergic reaction during epinephrine administration could be caused by one of the preservatives (e.g., bisulfites, antioxidants) added during manufacture. These have to be exceedingly rare

Next time if you are are trying to sleep, try warm milk.