Food Allergies and Medications

Medicines that contain food proteins, such as soy, eggs, milk, or components of shellfish, can potentially trigger allergic reactions.

Food allergies are becoming more common, with approximately 8% of children and 5% of adults suffering from at least one food allergy. It can be difficult for people to avoid their food allergen(s), and accidental exposure resulting in allergic reactions can occur.

The U.S. Food Allergen Labeling and Consumer Protection Act of 2004 (FALCPA) requires that food labeling includes the eight most common food allergens present in packaged foods, including egg, milk, soy, wheat, peanut, tree nut, fish, and shellfish. While this legislation is helpful for identifying these allergens in foods, FALCPA does not cover prescription and over-the-counter medications.

So people with food allergies who are used to reading labels on foods to identify food allergens may erroneously assume certain medications are safe for them—but medications could contain potential food allergens, even if they aren't indicated on the label.

Full Frame Shot Of Multi Colored Pills
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Pharmaceutical products contain excipients, which are inactive ingredients required for the manufacturing process and to help with the stability and function of medications. Many excipients are food products that could potentially cause allergic reactions in people who are allergic to that specific food product.

As a result, many people with food allergies commonly avoid certain medications to reduce the chances of an allergic reaction due to a hidden food allergen. The following is a list of common food allergens and related medications containing relevant excipients.

Egg

Some medications use egg lecithin as an excipient, which contains some egg protein. However, allergic reactions to egg lecithin are rare in people with egg allergies.

Intravenous (IV) lipid emulsions contain egg and soy lecithin, and allergic reactions are more likely caused by the soy component than the egg protein.

Propofol is an anesthetic used during surgery and is well known to cause allergic reactions. While propofol contains soy and egg protein, most people who have an egg allergy can safely receive the medication. Skin testing can be performed for people who have experienced an allergic reaction as a result of taking this medication.

Fish

Protamine is obtained from salmon testes, and it is used as an ingredient in some forms of insulin and to reverse the anticoagulant effects of heparin. While allergic reactions have been reported in people receiving protamine, people with a fish allergy do not appear to be at a higher risk of reaction. People with a fish allergy can receive medications containing protamine.

Fish oil is used to provide high levels of omega-3 fatty acids because some people believe it may help prevent heart disease. Because fish oil is refined, it does not contain fish protein and can usually be safely taken in people with a fish allergy.

Gelatin

Gelatin is obtained from the connective tissue of cows and pigs, and it contains proteins from these animals.

Allergic reactions to gelatin are common, especially in injected medications and vaccines. Pills and capsules containing gelatin rarely cause allergic reactions in people with gelatin allergy. Suppositories containing gelatin capsules have been known to cause allergic reactions in people with gelatin allergy.

Erythropoietin infusions containing gelatin can cause allergic reactions in people with gelatin allergy. And Gelfoam sponges, used to stop bleeding during surgery, contain gelatin and have been linked to allergic reactions in people with gelatin allergy.

Gelatin in various types of IV fluids can cause allergic reactions in people with gelatin allergy, although these products are not used in the United States.

Milk

Most people with milk allergies do not have allergic reactions as a result of taking medications containing small amounts of milk protein. In general, these medications can be safely taken by people with a milk allergy. These medications include casein-based probiotics, lactose-containing asthma inhalers (such as Advair Diskus, Flovent Diskus, Pulmicort Flexhaler and Asmanex), and lactose found in methylprednisolone injections (a corticosteroid).

Other forms of pharmaceutical grade lactose and related molecules are rarely contaminated with milk protein, but if they contain milk protein, they have the potential to cause allergic reactions in people with a milk allergy.

Peanut

Peanut oil is used in dimercaprol, progesterone capsules, and valproic capsules. Because pure peanut oil is refined, it does not contain peanut protein and should not cause allergic reactions in people with peanut allergies.

Pine Nut

Pine nuts are a product of pine trees, which are the source of rosin, also known as colophony. Rosin is used as a tooth varnish, and there are not reports that it causes allergic reactions in people with a pine nut allergy.

Rosin/colophony is known to cause contact dermatitis in certain people, but this reaction would not necessarily occur in people who are allergic to pine nuts.

Sesame Seed

Many medications contain sesame oil, although medication-grade sesame oil usually doesn’t contain sesame protein, unlike food-grade sesame oil, which does. This means that medications that contain sesame oil, such as progesterone for injection, should usually be safe for people with sesame allergy.

Shellfish

Glucosamine, which has been reported in a small number of people to cause allergic reactions, is obtained from the shells of shellfish. A small number of studies evaluating more than a dozen people with shellfish allergy showed that glucosamine was safe to take.

The protein that usually causes shellfish allergy is not present in high amounts in the shell, and glucosamine derived from the shell is not thought to elicit reactions in persons allergic to only the protein contained inside shellfish.

Iodine, which is present in shellfish and intravenous dye (IV dye), has no relationship to allergic reactions caused by eating shellfish.

Soy

Soy is found in many medications, but it rarely causes allergic reactions in people with a soy allergy. Soy lecithin is found in some inhalers, mainly those used to treat COPD, such as Combivent and Atrovent. There have been reports of people with a history of soy allergy using these inhalers and experiencing worsening breathing symptoms, but it was never proven that the soy lecithin in the inhaler was the problem.

Soy oil is contained in intravenous lipid emulsions found in total parenteral nutrition (TPN), a source of nutrition used for critically ill patients who cannot eat. While allergic reactions have occurred with TPN, it has not been proven that this was as a result of soy allergy.

Amphotericin C is an IV medication used to treat fungal infections in critically ill patients. Soy phosphatidylcholine makes up the fatty component of the medication, which allows it to enter and kill the fungus. Allergic reactions to amphotericin B have been described, although these have never been blamed on soy allergy.

Always Check First

While the above generalizations are true for most people with food allergies, anyone with a severe, life-threatening food allergy should check with an allergist before taking a medication that may contain traces of a food allergen.

Also, because the amount of a food allergen present in drugs is not regulated, the amount can increase over time without any warning.


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  • Kelso JM. Potential Food Allergens in Medications. J Allergy Clin Immunol. 2014;133:1509-18.