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Learn more about Medications That Can Interfere With Skin Testing Results

Skin testing is a crucial diagnostic tool used to identify allergic sensitivities. However, certain medications can interfere with the accuracy of these tests, leading to false-negative results. To ensure the reliability of skin testing, it is important to discontinue specific medications prior to the procedure.

Oral Antihistamines

Oral antihistamines are commonly used to manage allergy symptoms, but they can significantly impact the outcomes of skin testing. Patients are advised to stop taking these medications at least five days before their appointment. Notable oral antihistamines include:

• Cetirizine (Zyrtec & Zyrtec-D)

• Desloratadine (Clarinex & Clarinex-D)

• Fexofenadine (Allegra & Allegra-D)

• Levocetirizine (Xyzal)

• Loratadine (Claritin)

• Diphenhydramine (Benadryl)

• Hydroxyzine (Vistaril, Atarax, and Rezine)

• Dexchlorpheniramine (Polaramine)

• Cyproheptadine (Periactin)

• Chlorpheniramine (Aller-Chlor, Chlor-Trimeton)

• Carbinoxamine (Karbinal ER, RyVent)

• Brompheniramine (Bromphen, Bromphed)

• Azatadine (Optimine)

• Doxylamine (Nyquil)

Nasal Sprays

Nasal sprays containing antihistamines can also interfere with skin test results. Patients using these products should discontinue them as directed. Examples include:

• Azelastine (Astelin, Astepro)

• Azelastine/Fluticasone (Dymista)

• Olopatadine (Patanase)

• Olopatadine/Mometasone (Ryaltris)

Eye Drops

Antihistamine eye drops may affect skin test results. Patients should avoid using these medications before their testing. Some of these include:

• Alcaftadine (Lastacaft)

• Azelastine (Optivar)

• Olopatadine (Pataday, Pazeo, Patanol)

• Bepotastine (Bepreve)

• Epinastine (Elestat)

• Ketotifen (Zaditor, Alaway)

• Pheniramine (Opcon-A, Visine-A)


Certain antacids that contain histamine H2-receptor antagonists can impact skin test results. Patients should refrain from using these medications, including:

• Ranitidine (Zantac)

• Famotidine (Pepcid)

• Cimetidine (Tagamet)

Anti-Nausea Medications

Medications used to control nausea can also interfere with skin testing. These should be stopped prior to testing:

• Dimenhydrinate (Dramamine)

• Meclizine (Antivert, Bonine)

• Promethazine (Phenergan)

• Prochlorperazine (Compazine)

Sleep Aids

Certain sleep aids containing antihistamines can affect skin test results. These should be discontinued before testing:

• Diphenhydramine (Benadryl, Tylenol PM, Advil PM)

Patients should always consult with their healthcare provider before stopping any medication. It is essential to follow medical advice to ensure the accuracy of allergy skin tests and avoid potential complications. Proper management and communication with healthcare providers can lead to better diagnostic outcomes and more effective treatment plans for allergic conditions.

Please download the latest do-not-take-before-testing list here.

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