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Use as advised on the label as dosage varies depending on the patient.
Overview:
Allergies can be treated with a variety of medications, including steroids and allergy shots, but an antihistamine is usually the first thing to try. Most antihistamines are available in pharmacies and shops, but some are only available with a prescription.
Medical Uses:
When you experience an allergic reaction, your body releases a chemical called histamine, which attaches to receptors on particular cells and triggers allergy symptoms. Antihistamines then stop allergy symptoms by decreasing or blocking histamines. The allergic reaction is then less severe and the symptoms are lessened.
Antihistamines are frequently used to treat a variety of allergies and hypersensitivity-related diseases, including:
hay fever (allergic rhinitis)
hives (urticaria)
allergic conjunctivitis
eczema (dermatitis)
asthma
reactions to bites and stings
Side-effects:
Some of the main side effects of antihistamines include:
Dry mouth
Drowsiness
Dizziness
Nausea and vomiting
Restlessness or moodiness (in some children)
Trouble peeing or not being able to pee
Blurred vision
Confusion
Drug interactions:
Examples of medicines that could cause problems if used with antihistamines include:
antidepressants
stomach ulcer or indigestion medicines
cough and cold remedies that also contain an antihistamine
Avoid drinking alcohol while taking an antihistamine as this can increase the likelihood to feel drowsy.
Dosing:
Antihistamines are not recommended to children less than 6 years old unless it is directed by a doctor.
Children 6 to 12 years of age—12.5 to 25 mg (or 1 capsule) every four to six hours or as directed by a doctor.
Adults and teenagers—25 to 50 mg (or 2 capsules) every four to six hours as needed or as directed by a doctor.
Notes:
If you have an enlarged prostate, heart disease, high blood pressure, thyroid issues, kidney or liver illness, bladder obstruction, glaucoma, or any other medical condition, you should first consult your doctor. If you are pregnant or nursing, you should also check with your doctor.
Citations:
“Antihistamine (Oral Route, Parenteral Route, Rectal Route) Proper Use.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 1 Feb. 2023, https://www.mayoclinic.org/drugs-supplements/antihistamine-oral-route-parenteral-route-rectal-route/proper-use/drg-20070373#:~:text=Adults%20and%20teenagers%E2%80%9425%20to,age%E2%80%94Use%20is%20not%20recommended%20.
“Antihistamine Medications: What's Available and Side Effects.” WebMD, WebMD, https://www.webmd.com/allergies/antihistamines-for-allergies.
“Antihistamines.” Healthdirect, Healthdirect Australia, https://www.healthdirect.gov.au/antihistamines.
Illinois, University of. “Over-the-Counter Antihistamines: Brands and Side Effects.” Healthline, Healthline Media, 14 Feb. 2023, https://www.healthline.com/health/allergies/antihistamine-brands#firstgeneration-brands.
NHS Choices, NHS, https://www.nhs.uk/conditions/antihistamines/.
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