Which medication should a client stop taking four days prior to an allergy test?

Antihistamines should be discontinued four days prior to an allergy test because they can interfere with the skin prick test results or serum IgE measurements used to diagnose allergies. These medications work by blocking the action of histamine, a chemical that is released during an allergic reaction, and they can suppress the body's natural response to the allergens being tested. This suppression may lead to false-negative results, making it difficult to accurately identify potential allergens for the patient.

In contrast, medications like codeine, albuterol, and fluticasone do not have the same direct effects on the body's histamine response as antihistamines do. Codeine, primarily an opioid pain medication, does not affect allergy testing results. Albuterol, a bronchodilator used to relieve asthma symptoms, typically does not impact allergic responses measured during testing. Fluticasone, a corticosteroid nasal spray, can influence immune system response but is not as significant an interference as antihistamines. Therefore, cessation of antihistamines is crucial for obtaining valid results from allergy testing.