Antihistamines for allergic rhinitis

Examples

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Examples of antihistamines now on the market include:

Older (first-generation) over-the-counter and prescription antihistamines

Brand Name	Chemical Name
Semprex-D	acrivastine

Brand Name	Chemical Name
Semprex-D	brompheniramine maleate

Brand Name	Chemical Name
Chlor-Trimeton	chlorpheniramine maleate

Brand Name	Chemical Name
Tavist-1	clemastine fumarate

Brand Name	Chemical Name
Benadryl	diphenhydramine hydrochloride

Brand Name	Chemical Name
Vistaril	hydroxyzine hydrochloride

Brand Name	Chemical Name
Phenergan	promethazine hydrochloride

Newer (second-generation) over-the-counter antihistamines

Brand Name	Chemical Name
Alavert	loratadine

Newer (second-generation) prescription antihistamines

Brand Name	Chemical Name
Astelin	azelastine

Brand Name	Chemical Name
Zyrtec	cetirizine hydrochloride

Brand Name	Chemical Name
Clarinex	desloratadine

Brand Name	Chemical Name
Allegra	fexofenadine hydrochloride

Antihistamines may be available as tablets, capsules, nasal sprays, or liquids. You can use them alone or combined with decongestants to treat allergic rhinitis.

How It Works

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Many symptoms of allergic rhinitis, such as sneezing, itching, and runny nose, occur when your body releases a chemical called histamine. Antihistamine medicines block histamine and may reduce your symptoms.

Why It Is Used

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You can use antihistamines to stop or reduce sneezing, runny nose, and watery and itchy eyes caused by an allergic reaction.

How Well It Works

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All of these antihistamines work equally well to relieve sneezing, itching, and runny nose.

• Antihistamines begin to provide relief in 30 minutes to 2 hours.
• Antihistamines dry up the runny nose caused by allergies, but they usually do not clear up stuffiness.

Side Effects

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The older (first-generation) antihistamines may:

• Make you sleepy or make it harder for you to concentrate.
• Affect your coordination, even when they do not make you drowsy.

Take care when using older antihistamines if you need to drive or operate dangerous or heavy machinery. After you take an antihistamine several times, you generally know when you will become sleepy. For some people the side effects become less severe after they take the medicine for a few days.

Other side effects may include:

• Dry mouth.
• A bitter taste in the mouth.
• Nausea and vomiting.
• Feeling restless or moody, especially in children.
• Inability to urinate (urinary retention).
• Blurred vision.
• Rapid heartbeat (tachycardia), from decongestants that combine antihistamines and decongestants.

Newer, second-generation antihistamines have fewer side effects. Many of the new antihistamines cause less drowsiness than older antihistamines or cause no drowsiness at all. Azelastine may cause drowsiness in some people, although this is not common.

Talk with your doctor before using antihistamines if you have:

• Glaucoma or other conditions that cause pressure inside the eye.
• Urinary problems due to an enlarged prostate.
• Thyroid conditions, such as an overactive or underactive thyroid.
• Liver, kidney, heart, or lung disease.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

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The newer (second-generation) antihistamines tend to cost more than the older (first-generation) antihistamines. They do not work any better than the older antihistamines.

You may only have to take some of the newer antihistamines once a day.

In general, antihistamines don't relieve nasal congestion well. They are often combined with a decongestant in one product.

Fexofenadine may cause menstrual cramps, nausea, and fatigue.

Older adults and women who are pregnant or breast-feeding should talk to their doctors before using antihistamines.

Azelastine has been approved for use in children older than age 12. Desloratadine (Clarinex) may be suitable for children as young as 6 months. Children cannot use all antihistamines. Always talk with your doctor and check the label before you give antihistamines to children.

Complete the new medication information form (PDF) (What is a PDF document?) to help you understand this medication.

Credits

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Author	Debby Golonka, MPH
Editor	Susan Van Houten, RN, BSN, MBA
Associate Editor	Pat Truman
Primary Medical Reviewer	Caroline S. Rhoads, MD - Internal Medicine
Specialist Medical Reviewer	Harold S. Nelson, MD - Allergy and Immunology
Last Updated	August 8, 2007