A instructor in above-mentioned course did mention that snorting a crushed tablet might be a expedited method of getting the medication on board, so you might be onto something, Gurby.
I hope it is acceptable for me to revive a month-old thread here, but as it is directly relevant to the OPs question I figured it is okay to show up late to the party.
As a wilderness paramedic and snakebite medicine specialist in Africa, I have encountered a number of anaphylaxis cases in the remote medicine environment (i.e. bush hospital in the middle of west Africa remote - very limited supplies and the buck stops at your feet). Most of these cases involved pediatric patients suffering from acute anaphylaxis in response to antivenom therapy. Over time, I have developed my own protocol for handling these cases and it pretty much meshes with what was discussed earlier.
At the earliest onset of symptoms indicating an allergic reaction, I immediately crush up 25 or 50 mg of diphenhydramine (depending on size of patient), mix it with a half oz or so of water, and have my patient knock it back while I have an airway. Infants or peds patients who could not swallow received IM promethazine 0.1 mg/kg. In all of these patients I had already established large bore IVs for antivenom administration, so venous access was already taken care of and I would throw a bag of NS or RL on the line and open it up wide. If I had injectable diphenhydramine available that would have been ideal and I would have pushed it IV, but the only diphenhydramine I had available was the bottle I brought with me and the only injectable H1 available in country was promethazine. No interest in destroying a tiny vein with IV phenergan hence the IM administration. Moving on...
First sign of anaphylaxis in all patients I treated was a dry cough of increasing frequency, followed by restlessness and pruritis. So at the first dry cough I got an H1 on board, generally a crushed up Benadryl slurry, set my watch for 30' (the time it took for the Benadryl to kick in across the board), and aggressively managed with fluids, Epi, and/or dexamethasone or betamethasone depending on what drug we had available at the time (constant shortages of essential drugs, even ran out of Epi once). The idea behind the Benadryl PO or phenergan IM was to head off the anaphylaxis before additional drugs became necessary, and in roughly 40% of cases I treated it seemed to do just that. Diphenhydramine slurry PO took 30' to kick in across the board, while the patients I treated with cetirizine did not benefit until the 60' mark. If I had ranitidine with me I would have given that too, but it was not an option.
Because I was working in the middle of nowhere in a constant state of triage with limited medications, I withheld Epi until it was necessary and stuck to fluids and antihistamines as long as possible. This meant watching each patient like a hawk from the time when the diphenhydramine was knocked back onwards. At the first sign of airway compromise, respiratory distress, decompensation, etc I would push Epi and/or corticosteroids depending on what I had available. Care was taken to prevent cardiac arrest from severe BP drop in the peds patients (fluids and positioning) and I was reading vitals every minute or so as the clinical picture developed.
Epi (1:1000) was administered 0.25 mc/kg generally working out to 0.25 mg IM for the youngsters and 0.5 mg IM for the adults, always in the lateral aspect of the thigh. Since I didn't have the luxury of weighing a critical patient in the middle of nowhere, I estimated on the generous side and gave an appropriate dose (i.e 0.5 mg Epi for adults vs 0.3, 0.25mg for most of my peds patients instead of 0.125). This was done because I was consistently finding the need to administer multiple doses of Epi to crashing patients before any benefit was achieved. Oftentimes I would have to transfuse a bag of whole blood to treat the critical anemia caused by the snake venom (carpet vipers cause a DIC syndrome), so some of these patients were getting a bag of blood as well as fluids and whatever drugs I was pushing. But many did not, and required only minimal care: preloading with a PO dose of diphenhydramine at the onset of symptoms, clinical observation, and Epi if the Benadryl was unable to head off the anaphylaxis.
Once stabilized, I put all patients on a regimen of antihistamines (phenergan, diphenhydramine, or cetirizine - but generally cetirizine at this point due to the longer half life) or an oral course of corticosteroids for the next 36-72 hours to prevent recurrence of anaphylaxis, which is uncommon but entirely possible.
Lastly, for those of us operating in the backcountry here, a practical means of doing this follows. Get your Epi pen ready by rubber-banding a few blister packs of diphenhydramine and ranitidine to the case. This way you won't lose it and will remember that it is there if you need it. At the onset of symptoms, sit your patient down and make them chew up the antihistamines if you have an airway available. If you have to give Epi, immediately after giving it remove the preloaded syringe from the plastic case by following the instructions from the paper "Retrieval of additional doses of epinephrine from autoinjectors". I highly recommend that everyone takes a look at this paper. Most of my patients have required several doses of Epi, and if you don't know how to get it out then you are sitting there with a dead patient and approximately 9 additional doses of epinephrine in your hand.
Direct link here:
http://www.wemjournal.org/article/S1080-6032(13)00094-X/pdf
Hope that proves helpful, or at least interesting!
-Wilderness911