Final answer:
Antihistamines are used to treat allergy symptoms by targeting histamine receptors, with H₁-antihistamines used for nasal symptoms and H₂-antihistamines for gastric issues. Avoiding antihistamines is important before allergy testing to ensure accurate results. Consultation with a healthcare provider is advised for chronic use or persistent allergy symptoms.
Step-by-step explanation:
Important NCLEX Teachings About Antihistamines
Antihistamines are medications commonly used to treat symptoms of allergies, such as nasal congestion, sneezing, or hives. H₁-antihistamines target the histamine H₁ receptors and are effective for allergic reactions in the nose and other related symptoms, as well as for insomnia and motion sickness. On the other hand, H₂-antihistamines act on histamine H₂ receptors in the stomach and help treat gastric acid conditions like peptic ulcers and acid reflux.
For accurate allergy testing, patients are often instructed to avoid allergy medications, including antihistamines, because these drugs prevent histamines from binding to receptors or being released from mast cells, potentially masking the true allergic response during the test. Additionally, chronic usage of antihistamines for persistent allergies can lead to unaddressed health problems such as asthma or sinusitis, necessitating a consultation with a medical professional. Note that antihistamines are typically short-term treatments and are available in both prescription and over-the-counter forms.