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Medication (Drug) Allergies

Medication (Drug) Allergies

Individuals can have reactions to almost any medication or drug.  Some of the reactions are truly allergic while others can be classified as an adverse side effect.  The vast majority of medication reactions are in fact due to an adverse side effect, however, there are people who have a real immune response to that medication causing a real allergy.


The symptoms of a drug allergy can vary depending on the drug and the severity of the allergic reaction.  Some common organ systems with their respective symptoms include:

  1. Skin:   Itching (pruritus), flushing, hives (urticaria)swelling (angioedema), fever, other types of rashes, etc.
  2. Eyes:  Itching, watery, redness, etc.
  3. Nose:  Nasal congestion, runny nose, itchy nose, etc.
  4. Mouth and Throat:  Itching, throat tightness, swelling of tongue, etc.
  5. Gastrointestinal:  Diarrhea, nausea, vomiting, abdominal pain, etc.
  6. Respiratory:  Shortness of breath, wheezing, coughing, throat tightening, etc.
  7. Cardiovascular:  Drop in blood pressure, increase in pulse rate, lightheadedness/dizziness, fainting, etc.
  8. Anaphylaxis:  A severe life-threatening systemic allergic reaction which involves at least 2 organ systems.

It is important to note that individuals can develop some of the above symptoms without having an allergic reaction.  Some of these symptoms can also be due to a normal adverse side effect.  It is relatively common, for example, for people to experience an upset stomach and diarrhea while taking antibiotics.  Aspirin and NSAID’s (Nonsteroidal anti-inflammatory drugs) are common causes of abdominal pain, stomach ulcerations, and bleeding which is usually not caused by an allergy to these medications, although these medications also cause allergic symptoms in many individuals.  Common NSAID’s are Ibuprofen (Advil; Motrin), Naproxen (Aleve; Naprosyn), Indomethacin (Indocin), Piroxican (Feldene), Celecoxib (Celebrex), Meloxicam (Mobic), and Diclofenac (Voltaren).  It is therefore important for the patient to discuss with their doctor any symptom they are experiencing while on any medication to determine if the physician wants the patient to discontinue the medication in question.  Medications are frequently discontinued for a wide variety of reasons besides an allergic reaction.  There may be untoward side effects, interactions with other medications being taken, and/or a female patient may be planning or has just become pregnant and their medications need to be changed, to name a few.

Common Medication Allergies:

As mentioned above, almost any drug or medication can cause an allergic reaction.  There are, however, some medications that seem to cause allergic reaction more frequently than others.  These include:

1.)   Antibiotics:  (Note:  All antibiotics have the potential for causing allergic reactions)

A.  Penicillins (and all related derivatives):  Most common antibiotic allergy; about 10% “say” they are allergic to penicillins, but the actual percentage is much less.

B.  Cephalosporins (and all related derivatives):  A small percentage of penicillin-allergic individuals do have cephalosporin allergies.

C.  Sulfonamides (and all related derivatives):  Sulfonamides (also referred to as “sulfa”) can be found in antibiotics [i.e., Trimethoprim/sulfamethoxazole (also known as Bactrim or Septra), sulfisoxazole, sulfadizine, and dapsone.  Some water or fluid pills (diuretics) contain sulfa and Hydrochlorothiazide (HCTZ or Microzide) and Furosemide (Lasix) are two of them. Some oral diabetic medications (sulfonylureas) including but not limited to Glyburide (Micronase), Glipizide (Glucotrol), and Glimepiride (Amaryl) also contain sulfa.  Certain migraine medications such as Sumatriptan (Imitrex; Treximet) and NSAID’s such as Celecoxib (Celebrex) may be associated with adverse reactions in some individuals allergic to sulfa drugs.  If you have HIV or AIDS, you may have an increased sensitivity to sulfonamide medications.  Topical preparations such as sulfacetamide eye drops, creams, and/or shampoos, silver sulfadiazine creams and/or ointments, and sulfanilamide containing vaginal creams and/or lotions also contain sulfonamides.  Sulfasalazine (Azulfidine), a drug used to treat conditions such as Inflammatory Bowel Disease (Ulcerative colitis or Crohn’s disease), and Rheumatoid arthritis also is a sulfonamide.  Note that if you have a reaction to a sulfonamide antibiotic, one may still be able to take other sulfonamide medications without having a reaction.  One’s physician may still want to put selected patients on the non-antibiotic sulfonamide medications if needed, since these medications are usually tolerated better in “sulfa-allergic” patients than the sulfa antibiotics.  Always make your physician aware and discuss these options with him or her.

D.  Tetracyclines (and all related derivatives):  Note that tetracyclines can also cause photosensitivity and sunscreen should be worn, if one needs to go into the sun while on this class of medications.

E.  Macrolides (and all related derivatives):  Some macrolides include Erythromycin, Clarithromycin (Biaxin), and Azithromycin (Zithromax; Z-pak).

2.)  Aspirin and NSAID’s:  Although any allergic symptom can occur in those taking aspirin and/or NSAID’s, it is fairly common for individuals to become itchy and/or develop hives (urticaria) while on these medications.  A true IgE-mediated allergic reaction accounts for symptoms found in some individuals, however, in many situations, the symptoms instead are not caused by an IgE-mediated allergic reaction but rather a non-allergic activation of mast cells and basophils in one’s body which release chemicals into the bloodstream.  These chemicals (i.e., histamine, leukotrienes) are responsible for causing similar symptoms such as itching, hives, flushing, drop in blood pressure, and/or exacerbation of asthma.  There is also a condition known as Samter’s Triad or Aspirin- Exacerbated Respiratory Disease (AERD) which consists of nasal polypsasthma, and Aspirin/Nonsteroidal anti-inflammatory drugs (NSAID) sensitivity.  In this condition, Aspirin and/or NSAID’s can exacerbate the patient’s asthma and/or allergic rhinitis symptoms.  These patients must avoid Aspirin and NSAID’s.

3.)  Opioids:  Common opioids include Codeine, Hydrocodone, Hydromorphone, Levorphanol, Morphine, Oxycodone, Pentazocine, Methadone, Propoxyphene, Meperidine, and Fentanyl.  Opioid allergies are not common, but as with Aspirin and NDAID’s, many of the reactions can be due to a non-allergic mechanism through mast cell and basophil activation.

4.)  Anticonvulsants:  These are medications primarily used to treat and prevent seizures.  As a whole, these medications have a higher incidence of allergic reactions.

5.)  Insulin:  Occurs in about 2% of diabetics.  The frequency has decreased over the years, probably because “human” insulin is used more than decades ago when porcine (pig) and bovine (cow) versions of insulin where much more commonly used.

6.)  IV Contrast Dyes (Radiocontrast media):  These IV (intravenous) dyes are generally used in radiographic procedures (CT scans, angiograms, etc.) and technically are not IgE-mediated.  The reactions are non-allergic and are probably due to release of certain chemicals from mast cells and basophils.  They are referred to as “anaphylactoid” or anaphylactic-like reactions.  Despite this, they can be very serious and potentially fatal.  There are 2 types of IV dyes used in most procedures. There are ionic high-osmolality radiocontrast media and non-ionic low-osmolality radiocontrast media. The non-ionic low osmolality radiocontrast media is safer, particularly in individuals with risk factors, however, it is more expensive.  A recent study from the American Journal of Medicine stated that mild reactions occur in approximately 5-8% of patients receiving the IV contrast dye.  Moderate reactions occur in about 1% of the population.  About 0.1% (1 in 1,000) of individuals will experience a severe reaction with a death rate of about 1 in 75,000.  Mild and moderate reactions occur more often with ionic high-osmolality radiocontrast media, but the severe reactions and death rates are similar despite which radiocontrast media is used.  There are a number of risk factors which increase the likelihood of one developing a reaction to IV contrast media.  Some of these risk factors include:

Risk Factors for Reactions to IV Radiocontrast Dyes:

  1. Previous reaction to IV contrast media
  2. History of allergies
  3. Asthmatics
  4. History of heart disease
  5. History of kidney disease
  6. History of thyroid disease
  7. Elderly patients
  8. Patients on beta blocker medications (Metoprolol, Propranolol, Atenolol, Nadolol, etc.)
  9. Patients on Metformin (Glucophage)
  10. Females

Note:  There is a myth that people allergic to iodine or shellfish cannot be given IV contrast dye. It is the proteins in the shellfish that cause individuals to be allergic to shellfish, not the iodine. It is recommended that the patient discuss their shellfish or iodine allergy with an allergist, radiologist, and their ordering physician anyway, so they are aware of your history and then an informed decision can be made by the you with the input of your doctors. There are pre-medication protocols that can be given before an IV contrast dye is given which may help reduce or prevent a reaction.  Anyone who is told that they need to be administered IV contrast dye, should also speak with an allergist, radiologist, and their ordering physician before they undergo such a procedure to discuss the risks and alternatives.

Local Anesthetics:

This is a class of medications where a patient seeks an allergist to rule out an allergy quite often, despite the rare nature of an allergy to these drugs.  These “caine” drugs, as they are often referred to because all of these medications end with the suffix “caine.”  They are used mostly for numbing the mouth for dental procedures and numbing the skin for people getting sutures (stiches) include many different medications.  The “caine” drugs are also used to reduce pain locally in the eyes, nose, throat, spine, joints, as well as other locations.   Some of the “caine” drugs available include:

  1. Lidocaine (Xylocaine; Lignocaine)
  2. Prilocaine (Citanest)
  3. Bupivacaine (Marcaine; Sensorcaine)
  4. Mepivacaine (Carbocaine; Polocaine)
  5. Ropivacaine (Naropin)
  6. Levobupivacaine (Chirocaine)
  7. Dibucaine (Nupercainal; Nupercaine; Cinchocaine; Sovcaine)
  8. Etidocaine (Duranest)
  9. Procaine (Novocaine; Novocain)
  10. Cocaine (Benzoylmethylecgonine)
  11. Tetracaine (Amethocaine; Pontocaine; Altacaine, Opticaine)
  12. Benzocaine (Americaine; Cepacol; Lanacane; Anbesol; Orajel; Solarcaine)

Note that there are 2 classes of “caine” drugs.  There are the amide local anesthetics (1 through 8 above) and there are the ester local anesthetics (9 through 12 above).  Allergic reactions are more likely to occur in the ester group.

Risk Factors for Medication Allergies:

In general, there are risk factors for medication allergies.  Some risk factors associated with the patient includes gender, age, genetic predisposition, history of allergies and/or asthma.  There are also risk factors that are drug specific and some of these include the route of administration, dose, length of treatment, recurrent exposure to the drug, and concurrent diseases.  A medication allergy is more likely to occur with higher doses, longer durations of therapy, and with IV administration vs. oral administration.

Diagnosis and Treatment:

The diagnosis of medication allergies begins when a board certified allergist takes a thorough history and physical examination.  If necessary the allergist will perform skin testing and/or blood testing.  Oral challenges are occasionally done, if needed.  We also perform desensitization for the approved medications if such a procedure is warranted.  We are happy to see you at any of our 3 convenient offices in the Washington, DC, Northern Virginia, and Maryland metropolitan area.  We at Black & Kletz Allergy have office locations in Washington, DC, McLean, VA (Tysons Corner, VA), and Manassas, VA.  We have on-site parking at all 3 locations and we are Metro accessible at our Washington, DC and McLean, VA offices.  Please call us at your earliest convenience to schedule an appointment or you may Request an Appointment online and we will be in touch with you within 24 hours on the next business day.