Sedating antihistamines and
Oral antihistamines can also help treat the symptoms of eye allergies.
Antihistamines are also available as nasal sprays for the treatment of allergic rhinitis (nasal allergies) and as eye drops for the treatment of allergic conjunctivitis (eye allergies).
Most antihistamines can be bought from pharmacies and shops, but some are only available on prescription.
This page covers: Types of antihistamines How to take them Side effects Taking them with other medicines, food or alcohol Who can take them – including pregnancy advice How they work There are many types of antihistamine.
Some people find certain types work well for them and others do not.
You may need to try more than one type to find one that works for you.
For example, when you're fighting a cold (the rhinovirus), histamines widen the blood vessels in your nasal cavity, causing nasal congestion.
Additionally, the increased fluid leakage from your blood vessels, combined with an increased mucous production — also caused by histamines — can result in a runny nose.
Here, the histamines induce an inflammatory response — they dilate the blood vessels, increasing blood flow to the site of injury or invasion.Older antihistamines, such as diphenhydramine (Benadryl), chlorpheniramine (Chlor-Trimeton), and hydroxyzine (Atarax), also work well but have many side effects.Oral antihistamines work well when taken as-needed, meaning that allergy symptoms improve within an hour or two of taking the medication.Antihistamines for Hives (Urticaria)Oral antihistamines are the main treatment for hives.
Newer, low-sedating antihistamines, such as Zyrtec or Claritin, are preferred over the older, sedating antihistamines such as Benadryl or Atarax." April 25, 2003 -- Timely research for the start of hay fever season: Despite their higher cost, the newer, so-called "second generation" of more expensive "nonsedating" prescription antihistamines may be no more effective at preventing fatigue and memory lapses than older over-the-counter formulas such as Benadryl.