I hear it all the time: "I can't take any medications. I'm allergic to everything!" Some of my patients provide a long list of medicines to which they are allergic, often ruling out any reasonable hope of medicinal therapy for their condition. Others are appropriately concerned about side effects, noting that they would rather not take a medication "if it's going to make me sleepy" or cause other problems.
For most people, it's highly unlikely that they are unable to tolerate any medication or have "global allergies" to all medicines. Medication allergies and side effects are critically important issues that all patients and health care professionals must keep in mind. They account for up to 5% of hospital admissions in the United States and contribute to complications in another 5% of inpatient stays. But many "allergies" presumed to be dangerous are actually based on false assumptions, or represent side effects quite separate from an allergic reaction.
And this distinction matters: excessive concern about side effects or unsubstantiated allergies could lead you to not receive the most effective therapy.
Allergy or intolerance?
Some definitions are in order when thinking about medicines and possible problems they may cause. A true allergy is one type of side effect in which the immune system overreacts to what it sees as a foreign substance. Thus, all drug allergies are side effects, but not all side effects (also called a drug intolerance or adverse reaction) are allergies.
You'll want to avoid any medication that caused a significant problem for you in the past, regardless of whether it was due to an allergy or another type of side effect. On the other hand, it pays to be careful before considering yourself allergic to a medicine that might be very helpful for your particular condition.
Drug allergies. Allergic reactions are handled by the body's immune system, the surveillance and defense systems that help us fend off invaders, such as infections. Medication exposure may lead to several types of allergic reactions, ranging from a mild rash to life-threatening breathing difficulties and lowered blood pressure (also called anaphylaxis or anaphylactic shock). Fortunately, fewer than 5% of allergic reactions are severe.
Drug intolerance. Most of the time, medication intolerance has nothing to do with the immune system or any allergic component. A good example is the gastrointestinal side effects of the antibiotic erythromycin. Common side effects are nausea, abdominal cramping, and diarrhea. Up to 25% of people develop significant problems of this sort due to a direct effect of the antibiotic on the intestinal tract. But these problems are not due to an allergic reaction, and a lower dosage of the medication or a different formulation (such as a capsule instead of a pill) of the same antibiotic might be well tolerated. A "newer generation" antibiotic in the same family as erythromycin (such as clarithromycin) might be well tolerated in this situation. On the other hand, if a significant allergic reaction occurred, such as a severe rash or wheezing, these other options would be much more risky and should be avoided.
It's usually possible to distinguish an allergic reaction from another type of side effect by the type of reaction. Rash or breathing problems are more likely to be allergic, while diarrhea, constipation, and sleepiness are common non-allergic side effects. If you aren't sure whether you've had an allergic reaction to a medication or whether you should avoid taking a particular medicine in the future, ask your doctor.
Risk vs. expectation
The notion that someone is allergic to many, most, or even all medications is almost always a myth. The chances that an individual would be allergic to multiple, unrelated medicines are small — not impossible, but quite rare. Similarly, it's important to note that the risk of a side effect does not mean that the side effect will definitely occur if you take the medication. In fact, most side effects occur in only a minority of cases.
For the vast majority of medicines, there is a small chance that it will cause a problematic side effect — generally, that risk is less than 10%. In fact, if a particular medicine usually caused significant problems, that medicine would be unlikely to win approval by the U.S. Food and Drug Administration, and even if it did, physicians would be wary to prescribe it.
When considering an alternative, it is important to recognize that a medicine's therapeutic action and a side effect may be related to one another, unrelated to one another, or the relationship may be unknown. For example, a medication for diarrhea can cause constipation; in this situation, the "side effect" is really the medicine doing what it's intended to do (though, perhaps, too well). But codeine can also cause constipation, a side effect that is not directly related to its pain relieving action. In confusing situations when a particular medicine seems vitally important to take, allergy testing and even desensitization (in which tiny but increasing amounts of the medicine are taken to minimize the risk of a severe reaction) may be warranted.
The Bottom Line
The next time a medication is recommended to you, carefully consider the risks and benefits, including any unfavorable reactions you may have had with it in the past. But, don't swear off the medicine without first discussing with your doctor whether you are actually allergic to it. Otherwise, you may be turning down a highly effective and acceptably safe treatment. Just as all treatments come with risk, non-treatment also has risks.
Are you allergic to any medications? Do you have side effects to many medications? Tell me about the challenges you've faced taking medications.
Robert H. Shmerling, M.D. is an Associate Physician at Beth Israel Deaconess Medical Center. He is also a Senior Medical Editor for Harvard Health Publications.
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Comments: 5
It's a fine balance. I'm still trying to find mine, but I feel pretty good that I'm selecting the best from both worlds for my well being.
I also provide my doctor(s) with a printed list of every medication (and how many mgs) I take, all of my vitamins and supplements, emergency contacts, allergies, and other doctors I see regularly for medical issues. They seem to really appreciate the information so they have it all at hand when considering treatment. I think it would be so helpful to both patient and doctor for patients to always carry this around with them in their wallet. It's also something important to have should one get in an accident. I have mine folded up and in a noticeable 'window' in my wallet written in RED ink, "MEDICAL INFO FOR NANCY M."
Didn't mean to get off on to this tangent, but I hope this helps anyone who stops by to read your article, Doctor Schmerling!
I am blessed to have some excellent doctors and specialists, and we work as a team to find out what works best for me, and thoroughly discuss pros and cons of medications or procedures to decide on the best plan of action. They always have me check back with them if I'm taking a new medication to see how effective it is, or if there are any problems with it. I would not want to enlist the services of a doctor who would treat me as someone who doesn't know my own body or who wouldn't listen to my thoughts and concerns regarding a treatment. I have a great team of doctors!
I am under the immunologist at the moment and have been told there is nothing they can do for me as nobody has a resolution for my problem, they are trying to find me a suitable antibiotic and painkiller and that is it.
I am not allergic to any of the medication i have taken, my body rejects it, after 3 days of ANY medication i get rounded red eyes, 4th day i get a large triangular red rash top half of my back which burns from the inside to the outside the next day it hits my brain and my personality changes to being violent and aggressive , confused..I have never chanced going any further as those warnings are enough for me and none of these symptoms are allergies i have been tested. I am 54yrs old and have had this all my life only now have i brought this to attention.
regards Marilyn
I read your comment and really feel for you. I have not been intolerant all my life, but have become so over the past 19 years. Now I cannot tolerate any type of medication, prescription or over-the-counter, including vitamins and supplements. I have not found a physician who can appreciate this and, like you, have no options. My ongoing drug intolerance was part of an ever evolving condition known as Multiple Chemical Sensitivities. In addition to medications, I can no longer tolerate most chemicals that are common in our everday environment. My side effects from medication are somewhat different from yours, and can vary depending on the medication: migraines, chest pains, palpatations, fatigue, acne, dangerously high blood pressure, asthma, anaphylaxis, brain fog, personality changes,photosensitivity....and the list goes on. I, like you, do not want to try anything else, as I have been abused 100% of the time, and it gets worse with each medication. I know it is not much solace, and that our conditions are different, but you are not alone in your situation. I am now 51 and would rather die than take another drug. I'm not a drama queen, I don't have a death wish, but I'm also not a masochist and can't tolerate the abuse. I don't know where we can find answers, but I keep looking. I'm glad you were mentioned at the seminar....stories like yours need to be told.
I wish you well,
Lauren