Allergies Health Center

Allergy Medications

In general there is no cure for allergies, but there are several types of medications available -- both over-the-counter and prescription -- to help ease and treat annoying symptoms like congestion and runny nose. These allergy drugs include antihistamines, decongestants, combination drugs, 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: Allegra, Benadryl, Claritin, Chlor-Trimeton, Dimetane, Zyrtec, and Tavist. Ocu-Hist is an OTC eye drop.
• Prescription: Clarinex and Xyzal are oral medications. Astelin is a prescription nasal antihistamine spray and prescription antihistamine eye drops include Patanol and Elestat and Optivar.

How Do Antihistamines Work?

When you are exposed to an allergen , for example ragweed pollen,  it triggers your immune system. People with allergies demonstrate an exaggerated immune response.  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 and keeping it from binding to receptors, antihistamines prevent these symptoms.

What Are the Side Effects of Antihistamines?

Many older over-the-counter antihistamines may cause drowsiness. Newer, non-sedating second and third generation antihistamines are available over-the-counter or by prescription.

Decongestants

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

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

Some examples of decongestants include:

• Sudafed tablets or liquid, Neo-Synephrine and Afrin nasal sprays, and some Visine eye drops are available over the counter. 
• Combination decongestant and antihistaminemedications such as Allegra-D or Zyrtec-D can be prescribed or bought over the counter.

How Do Decongestants Work?

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

What Are the Side Effects of Decongestants?

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