First-generation OTC oral antihistamines, including diphenhydramine and chlorpheniramine, are the oldest group. First-generation brands include Benadryl and Chlor-Trimeton. The first-generation antihistamine diphenhydramine is the main active ingredient in Benadryl.
Benadryl helps relieve runny nose, sneezing, itchy or watery eyes, and nose or throat itching. These symptoms may be due to hay fever , other upper respiratory allergies, or the common cold. Benadryl can also be used to treat hives and to reduce redness and itching. It comes in a tablet, a chewable tablet, a tablet that dissolves in your mouth, a capsule, a liquid-filled capsule, and a liquid. Benadryl also comes in topical forms, such as creams, gels, and sprays, to treat allergic skin conditions such as hives.
Chlorpheniramine is the main active ingredient in Chlor-Trimeton. It helps relieve runny nose, sneezing, itchy or watery eyes, and nose and throat itching from hay fever. It also helps relieve other respiratory allergies. It comes in an immediate-release tablet, an extended-release tablet, a chewable tablet, a lozenge, a capsule, and a liquid.
If you have an enlarged prostate that makes it difficult for you to urinate, you should talk to your doctor before using first-generation antihistamines. These drugs can make your urination problem worse. You should also talk to your doctor before using these drugs if you have any of these health concerns:.
If you take other drugs that can make you drowsy, such as sedatives or tranquilizers, talk to your doctor before using first-generation antihistamines. You should also avoid drinking alcohol with any antihistamine because it can increase the side effect of drowsiness.
Mixing benadryl and alcohol has several distinct dangers to be…. Allergic reactions are numerous and varied, and the best treatments depend on the specific symptoms, such as rashes or sinus problems, and their…. In this article, learn about what eye drops are available for itchy eyes, when eye drops should be used, and when people should see a doctor.
An allergy develops when the immune system becomes hypersensitive to a food or other substance. Learn how to identify and manage allergies here. What are antihistamines? Medically reviewed by Alan Carter, Pharm. Overview Symptom relief Types Side effects and risks Summary We include products we think are useful for our readers. What are they, and how do they work? Share on Pinterest A person may take antihistamines to treat allergic rhinitis.
What symptoms do they treat? Side effects and risks. Latest news Scientists identify new cause of vascular injury in type 2 diabetes.
Adolescent depression: Could school screening help? Related Coverage. Zyrtec vs. Background: Histamine is responsible for the wheal and flare reaction in various allergic conditions. Classical antihistamines are the drugs which block the H 1 receptors and are widely used in various allergic conditions, whereas H 2 blockers are mainly used for acid peptic disease.
Although H 1 receptor-mediated actions of histamine are primarily responsible for vasodilatation, vasopermeability, and itching, it has been observed that combined blocking of both H1 and H2 receptors may provide better relief. Indeed, mast cells themselves have H4 receptors which when stimulated increased degranulation and cytokine production. Therefore, antihistamines targeting both the H1 and H4 receptor could be an effective treatment for mast cell-mediated allergic diseases Pharmacological properties of H4R have been exhibited by various H4R transfected cells 87 , 89 , 99 , , However, some H3R ligands such as imetit, clobenpropit, thioperamide, and R -methylhistamine are also able to bind to the H4R with different affinities.
Currently, a number of H4R antagonists have been developed but only a few are undergoing clinical trials. JNJ , a potent and selective H4R antagonist, has shown impressive results in different allergic inflammatory diseases such as dermatitis, asthma, pruritus, and arthritis , Interestingly, the combination therapy of this H4R antagonist and the H1R antihistamine, cetirizine, showed a more beneficial effect in the treatment of pruritus as compared with H1R alone — Furthermore, a study was carried out by using JNJ to treat persistent asthma NCT , but no results have yet been reported.
However, a study in rheumatoid arthritis NCT was terminated due to issues related to efficacy. The recent developments in research on histamine pathway underscore the importance of histamine in allergic inflammation through its effects on the H1R and H4R. Although, drugs targeting H1R are being explored for the treatment of various mast cell-associated allergic disorders, they are not always clinically effective. Several H4R antagonists have entered the later stages of clinical trials for a different range of allergic and inflammatory diseases.
However, their clinical efficacy reports are not yet published. Furthermore, there appears to be some overlap in function between H1R and H4R, opening up the possibility for using synergistic strategies for therapeutic approaches.
As such, we suggest the combination therapies by using both H4R together with H1R antagonists may provide a potential benefit in the treatment of various allergic and inflammatory diseases. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Rothenberg ME. N Engl J Med — Kay AB.
Allergy and allergic diseases. First of two parts. N Engl J Med —7. Nature —6. Identification, purification, and characterization of a mast cell-associated cytolytic factor related to tumor necrosis factor. Histamine induces cytoskeletal changes in human eosinophils via the H 4 receptor. Br J Pharmacol — Histamine H4 receptor mediates chemotaxis and calcium mobilization of mast cells.
J Pharmacol Exp Ther — Identification of a histamine H4 receptor on human eosinophils — role in eosinophil chemotaxis. J Recept Signal Transduct Res — A potent and selective histamine H4 receptor antagonist with anti-inflammatory properties. Inflamm Res — Histamine regulates T-cell and antibody responses by differential expression of H1 and H2 receptors.
Nature —5. Histamine upregulates Th1 and downregulates Th2 responses due to different patterns of surface histamine 1 and 2 receptor expression. Int Arch Allergy Immunol —2. Histamine induces exocytosis and IL-6 production from human lung macrophages through interaction with H1 receptors.
J Immunol — Enhancement of neutrophil infiltration in histidine decarboxylase-deficient mice. Immunology — Histamine H4 receptor mediates eosinophil chemotaxis with cell shape change and adhesion molecule upregulation. Functional expression of H4 histamine receptor in human natural killer cells, monocytes, and dendritic cells.
Histamine and its receptors. Br J Pharmacol Suppl 1 :S— Apoptosis in the airways: another balancing act in the epithelial program. Histamine in allergic inflammation and immune modulation. Int Arch Allergy Immunol — Histamine receptors are hot in immunopharmacology. Eur J Pharmacol — Int Immunopharmacol — Mast cell functions in the innate skin immune system. Immunobiology — Saito H. Mast cell research. Chem Immunol Allergy — Mast cells.
Physiol Rev — Immunoglobulin E-independent activation of mast cell is mediated by Mrg receptors. Biochem Biophys Res Commun —8. Theoharides TC. The mast cell: a neuroimmunoendocrine master player. Int J Tissue React — PubMed Abstract Google Scholar. Critical role of mast cells in inflammatory diseases and the effect of acute stress.
J Neuroimmunol — Tal M, Liberman R. Local injection of nerve growth factor NGF triggers degranulation of mast cells in rat paw. Neurosci Lett — Mol Immunol —5. Barnes PJ. Histamine receptors in the lung. Agents Actions Suppl — Google Scholar.
Hill SJ. Multiple histamine receptors: properties and functional characteristics. Biochem Soc Trans —5. Zampeli E, Tiligada E. The role of histamine H4 receptor in immune and inflammatory disorders. Jutel M, Akdis CA. Histamine as an immune modulator in chronic inflammatory responses.
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