Allergy Medications

There is no cure for allergies, but there are several types of medications available -- both over-the-counter and prescription -- to help ease annoying symptoms like congestion and runny nose. These allergy drugs include antihistamines, decongestants, combination medicines, corticosteroids, and others.

Allergy shots, which gradually increase your ability to tolerate allergens, are also available.

Antihistamines

Antihistamines have been used for years to treat allergy symptoms. They can be taken as pills, liquid, nasal spray, or eye drops. Over-the-counter (OTC) antihistamine eye drops can relieve red itchy eyes, while nasal sprays can be used to treat the symptoms of seasonal or year-round allergies.

Examples of antihistamines include:

• Over-the-counter: Benadryl, Claritin, Chlor-Trimeton, Dimetane, Zyrtec, and Tavist. Ocu-Hist is an OTC eye drop.
• Prescription: Clarinex and Allegra. Astelin is a prescription nasal spray. Eye drops include Emadine and Livostin.

How Do Antihistamines Work?

When you are exposed to an allergen -- like ragweed pollen -- it triggers your immune system to go into action. Immune system cells known as "mast cells" release a substance called histamine, which attaches to receptors in blood vessels causing them to enlarge. Histamine also binds to other receptors causing redness, swelling, itching, and changes in secretions. By blocking histamine receptors, antihistamines prevent these symptoms.

What Are the Side Effects of Antihistamines?

Many over-the-counter antihistamines cause drowsiness. Non-sedating antihistamines are available by prescription.

Decongestants

Decongestants relieve congestion and are often prescribed along with antihistamines for allergies. They come in nasal spray, eye drop, liquid, or pill form.

Nasal spray and eye drop decongestants can be used for only a few days, since long-term use can actually make symptoms worse. Pills and liquid decongestants may be taken longer safely.

Some examples of decongestants include:

• Over-the-counter: Zytec-D, Sudafed tablets or liquid, Neo-Synephrine and Afrin nasal sprays, and Visine eye drops.
• Prescription: Prescription decongestants include drugs like Claritin-D and Allegra-D that combine a decongestant with another allergy medicine.

How Do Decongestants Work?

During an allergic reaction, tissues in your nose swell in response to contact with the allergen. That swelling produces fluid and mucous. Blood vessels in the eyes also swell, causing redness. Decongestants shrink swollen nasal tissues and blood vessels to relieve the symptoms of nasal swelling, congestion, mucous secretion, and redness.

What Are the Side Effects of Decongestants?

Decongestants may raise blood pressure, so they are not recommended for people who have blood pressure problems or glaucoma. They may also cause insomnia or irritability and restrict urinary flow.

Combination Allergy Drugs

Some allergy drugs contain both an antihistamine and a decongestant to relieve multiple allergy symptoms. There are also other combinations, such as those between an allergy medicine and asthma medicine and an antihistamine eye drop with a mast cell stabilizer drug (see below).

Some examples of combination allergy medicines include:

• Over-the-counter: Zyrtec-D , Benadryl Allergy and Sinus, Tylenol Allergy and Sinus.
• Prescription: Allegra-D, Claritin-D, and Semprex-D for nasal allergies. Naphcon, Vasocon, Zaditor, Patanol, and Optivar for allergic conjunctivitis.