Talk about being caught between a rock and a hard place. It’s an emergency situation, so medical care is limited. There’s only one drug on hand and you desperately need medication. But you’ve had an unpleasant response – an adverse reaction- to that drug before. Should you take it? The answer may hinge on knowing if the unpleasant response was an ‘allergy’, a’side effect’, or an ‘interaction’.
Please note, I’m not a physician. I’m not offering medical advice; I’m offering some information from the world of medicine. Dr. Joseph Alton (who is an M.D.) motivated me to write this one when he brought up the problem in his very useful book Alton’s Antibiotics and Infectious Disease. (1)
What’s an ‘allergy’ really?
Imagine a mosquito lands on the head of a toddler. Well, that’s not a good place for a mosquito. So you smash it. With a hammer. (JUST imagine, Don’t try this at home!)
That is an allergy. Your immune system sees something that’s not you. It’s not particularly dangerous, but it’s not you. Your immune system goes into a frenzy and destroys everything in the vicinity in an effort to get rid of the ‘not you’. Unfortunately, everything in the vicinity is you. The damage in an allergy is done by your own immune system.
Hives are caused by an immune system that is way too worked up. Allergies often cause hives.
Allergic reactions come in different forms and range from annoying to deadly. Intentionally exposing yourself to something to which you have one of the deadly allergies (anaphylactic reactions) reminds me a lot of Russian roulette… perhaps even with multiple chambers loaded.
What’s a drug ‘side effect’ then?
First what it’s not: A side effect is not your immune system going nuts. It will not cause the potentially deadly anaphylactic shock.
All drugs have the potential to cause some extra effects that weren’t the reason the person took the drug. These are called side effects. If they’re harmful, they’re also called adverse drug reactions. Perhaps you’ve heard the old puzzle of “How does aspirin know where it hurts?” Well, the aspirin doesn’t know. It’s just a stupid molecule. It goes everywhere in your body and plays its biochemical roles wherever the relevant chemical reactions are occurring.
Take an aspirin to kill pain and it will also blood clotting. That’s a side effect. Take an aspirin to reduce your risk of a heart attack from inappropriate blood clotting and you’re less likely to get a headache. That’s also a side effect. The drug does not care why you took it.
Each drug has its own list of likely side effects. Some occur in everyone who takes the drug (as in the aspirin example). Other side effects happen only in a small percentage of people who take the drug, or only in people who take it for a long time. Most side effects get more common with higher doses of the drug, but the necessary dose to show the side effect varies from person to person.
Drug interactions are another kind of adverse reaction.
Adverse drug reactions are more frequent in people who take several medications. This is because not all drugs work and play well together. Some drugs have similar actions, so you can unintentionally overdo an action. Have some aspirin when you’re already on blood thinners and you might bleed for hours after a small cut. Sometimes two drugs interfere with one another. For example, a woman can’t rely on her birth control pills if she’s taking one of several sorts of antibiotics.
Here’s a sample of some drug interactions from an exceptionally common drug type, NSAIDS.
Each drug’s published information also includes what’s known about adverse interactions. Do you have a copy of that information printed out and stored with whatever drugs are in your prepper medicine chest? Wouldn’t that be nifty to have?
What does it matter what kind of adverse reaction it was?
If an adverse reaction was an allergy, it’s highly likely to recur. Not always; sometimes allergies are lost over the years; but often. Having any hint of an anaphylactic reaction and taking the same drug again later strikes me as a very dangerous proposition. The cure would be likely to be worse than the disease.
If the first problem was an interaction, the risk of recurrence depends the presence of the other drug. When the interacting drug is or can be dropped, problem solved. If you need both drugs, the nature of the interaction becomes important. Can you just manage the problem? Women on birth control are advised to use a backup form of contraception when they’re prescribed antibiotics, for example.
If you had a side effect the first time, it might or might not recur. The longer you take it and the more you take, the more likely most side effects become. (2) How you’d proceed in such a situation might depend on how harmful the side effects were; and how harmful they might be if they recurred in a more intense form.
There are other kinds of adverse reactions, such as overdoses and drug abuses. Those are beyond the scope of this article. (3)
How do you figure out what kind of adverse reaction it was?
Well, I’d start by asking the physician who managed the first response, if there was one. The drug’s published information is a useful source. Drugmakers must report all known side effects and interactions.
Since allergies are from the immune system rather than the specific drug, many allergic reactions look similar. Anaphylaxis, for example, includes hives and itching and flushed or pale skin. Low blood pressure and airway constriction causing wheezing and air hunger are the most dangerous effects. The pulse gets weak and rapid, and there may be nausea and vomiting. The low blood pressure may lead the person to pass out. (4)
Allergic reactions that might not turn as serious include rashes and swelling and tingling of lips and tongue. Ingested drugs might cause gut distress of various sorts. Other reactions are possible too, but those are the most common.
References
1) Alton, J, and Alton, A. 2018. Alton’s Antibiotics and Infectious Disease. Alton First Aid, LLC.
2) Edwards IR1, Aronson JK. Adverse drug reactions: definitions, diagnosis, and management.. Lancet. 2000 Oct 7;356(9237):1255-9
3) Adverse Drug Reactions. The Pharmacology Education Project (PEP), The International Union of Basic and Clinical Pharmacology (IUPHAR). Accessed 2-23-19. https://www.pharmacologyeducation.org/clinical-pharmacology/adverse-drug-reactions
4) Anaphylaxis. Mayo Clinic. Accessed 2-23-19. https://www.mayoclinic.org/diseases-conditions/anaphylaxis/symptoms-causes/syc-20351468