Medication Allergies: Everything You Need to Know

Medication allergies occur as a result of an immunologic reaction characterized by itching, hives, shortness of breath, rash and facial swelling. Most reactions are mild, but some can be life-threatening. Anaphylactic shock is the most serious kind of allergic reaction to a drug. The first time you take a medication, there may not be any symptoms as this is the initial exposure. But, during this time the body produces antibodies as protection against the drug because it is perceived as a pathogen or foreign body.

When you take the drug again, your body is prepared to fight the invader and white blood cells respond by producing histamine. Once histamine is released, symptoms start to occur and a chemical chain reaction ensues as more antibodies are made. Not all drug reactions are actual allergic responses, but are in fact side effects of a medication. Side effects, commonly called adverse drug reactions (ADR) are expected with certain drugs such as constipation when taking an opioid for pain. When you know you have had medication allergies before, it is essential to tell your doctor. Provide them with a list, if there are several drugs you are allergic to.

Common Drugs and Treatment

Although any drug can cause an allergic reaction, certain drugs have been known to produce medicine allergies in people. The following is a list of common medications (but does not include all) known to cause allergic reactions:

Chicken Protein Allergies

• All vaccinations that include the yellow fever vaccine.

Egg Allergies

• All vaccinations that include the flu and yellow fever vaccines.

Gelatin Allergies

• All vaccinations that include the flu, MMRV (MMR with chickenpox), yellow fever, shingles and varicella (chickenpox) vaccines.

Lactose (Milk) Protein Allergies

• Dry powder inhalers (DPIs) that are frequently labeled “Ellipta”. Example: Anoro Ellipta or Breo Ellipta. They are also frequently labeled “Diskus” as well. Example: Advair Diskus or Flovent Diskus.

Peanut Allergies

• Ear drops – Example: DermOtic (fluocinolone)
• Hormone capsules – Example: Prometrium (progesterone)
• Topical medications – Example: Derma Smoothe/FS (fluocinolone)

Penicillin Allergies

• Penicillin antibiotics – Example: ampicillin or amoxicillin
• Cephalosporin antibiotics – Example: cefdinir, cefuroxime and cephalexin

Sulfa Allergies

• Leprosy medication – Example: dapsone
• Urinary medications – Example: Flomax (tamsulosin)
• Burn creams – Example: Silvadene (silver sulfadiazine)
• Seizure medications – Example: Zonegran (zonisamide)
• Acne medications – Example sulfacetamide sodium lotion
• Antibiotics – Example: Bactrim (sulfamethoxazole/trimethoprim)
• Diabetes medications – Example: glimepiride,  glyburide and glipizide
• Anti-Inflammatory medications – Example: Celebrex (celecoxib) and sulfasalazine
• Water pills or Diuretics – Example: hydrochlorothiazide and Lasix (furosemide)
• Skin infection medications – Example: sulfacetamide sodium wash (shampoo or gel)
• Eye drops – Example: Bleph-10 (sulfacetamide) and Polytrim Solution (polymyxin b/trimethoprim)

Diagnosis and Prevention

While most types of medication allergies can be diagnosed with a skin test, this is not the case for those caused by medicine allergies. The only type of drug that can be diagnosed with a skin test is penicillin. Symptoms caused by allergic reactions to drugs are common to many types of allergies, not just medications. This makes it difficult to pinpoint the particular drug responsible for causing an allergic reaction.

Under most conditions, allergies are preventable by avoiding the known substance causing the problem. But in the case of medication allergies, this may not always be possible especially since you may not be aware of the allergy unless, of course, you’ve had a previous allergic reaction to a particular drug. Sometimes, doctors use something called desensitization to help a patient with medicine allergies. Desensitization involves a process of taking increased doses of the allergy-causing drug. The idea is that the body will increase its tolerance to the offending drug. Desensitization is an option when there are no other medicines available for treatment. This should only be done under the direction and care of a medical doctor who specializes in allergy treatment. They are referred to as allergists.