Dozens of drugs, avaiable either over the counter or by prescription, are available to treat allergy symptoms. These include antihistamines, which block the action of histamine, the chemical released by the body in response to an allergen; decongestants, which are best limited to short-term use when you are first gaining control over nasal symptoms; corticosteroids in spray or inhaler form to control nasal symptoms or asthma, or in oral form (prednisone) for asthma flares or certain severe allergy reactions; and topical (skin) corticosteroid ointments or creams to treat eczema. Finally, epinephrine is a life-saving injectable medicine that must be used to treat serious symptoms from anaphylaxis.
Many antihistamines and decongestants used to treat allergy symptoms are available without a prescription. Prescriptions are required for other drugs, such as steroid medications. Some antihistamines (both over-the-counter and prescription) can slow reaction times, impair judgment and make you sleepy. So you shouldn't drive or operate machinery while taking drugs with these side effects. Here's a list of common allergy medications: (For more complete data, check out our Drug Resource Center. )
Drugs That Prevent Allergy Symptoms
These drugs combat allergy symptoms, including sneezing, runny or itchy nose, watery or itchy eyes and hives. They work by blocking the action of histamine, the chemical released by the body in response to an allergen producing the reaction.
Histamine has many actions within the body, including stimulating the production of tears, nasal mucus, and saliva, and dilating small blood vessels and making them leaky (which helps explain why a rash often is part of an allergic reaction). Antihistamines work to counter these reactions.
Most antihistamines are available over the counter. Newer antihistamines (known as “non-sedating” or “second generation” antihistamines) cause drowsiness in fewer people, compared with the older antihistamines. Noticeable drowsiness is a side effect that occurs with older over-the-counter antihistamines in about 15 percent of people. “Non-sedating” antihistamines are more expensive than older versions.
Nonprescription: “First generation” medicines that are more likely to cause sedation include chlorpheniramine (Chlor-Trimeton), Diphenhydramine (Benadryl), clemastine (Tavist), and brompheniramine (an antihistamine ingredient in the combination product Dimetapp); these are available either as single ingredient or combination products and by generic or brand names, in tablet, capsule and syrup forms. “Second generation” or “non-sedating” medicines include loratadine (Claritin, Alavert, Tavist ND) in tablets, rapidly dissolving mouth tablets, and syrup. Cetirizine (Zyrtec tablets and syrup) is also available over-the-counter, but it is more sedating than loratadine.
Prescription:Non-sedating prescription antihistamines include fexofenadine (Allegra), desloratadine (Clarinex), and azelastine (Astelin nasal spray).
Common Side Effects: All oral antihistamines can cause drowsiness; impaired coordination, urinary retention (particularly a problem for men with prostate disease); and dry nose, mouth and throat. Make certain that you read the information provided with either over-the-counter antihistamines or those available only by prescription.
Precautions: All antihistamines, including those advertised as being non-sedating, have the potential to cause drowsiness. Sedation and drowsiness are more common with over-the-counter antihistamines. Don't drive or operate heavy machinery when taking these drugs. Tell your doctor about any drugs you are taking and about any other physical disorder you may have, especially urinary or prostate problems and glaucoma. Drinking alcohol can magnify the sedating effects of antihistamines.
Corticosteroid Nasal Sprays
Corticosteroids nasal sprays are an excellent treatment option to relieve nasal symptoms. Nasal corticosteroids are anti-inflammatory drugs that inhibit allergic reactions and reduce nasal swelling and mucus secretions. These sprays relieve congestion rhinitis and can diminish the size of nasal polyps if these tissue bulges are an additional cause of congestion. In clinical trials corticosteroid nose sprays are consistently better than oral antihistamines at relieving the nasal symptoms of runny, stuffy and itchy nose. Instead of being used as a “rescue” medicine for immediate relief of new symptoms, these medications typically are used on a regular schedule during allergy season.
Beclomethasone (Beconase, Vancenase), budesonide (Rhinocort), flunisolide (Nasalide), fluticasone (Flonase), mometasone (Nasonex) and triamcinolone (Nasacort).
Common Side Effects: Sneezing, an itchy, mild dryness or burning in the nose, and unpleasant taste, thrush (yeast infection in the mouth), nosebleeds, headaches.
Precautions: Rare reports have blamed these medicines for resulting in a hole in the nasal septum. Steroid nose sprays may slightly increase your risk for glaucoma, if they are used long term.
Cromolyn and Nedocromil
Cromolyn and Nedocromil are agents used in spray form. They interfere with the release of histamine and other chemicals from mast cells, and thereby prevent allergic asthma flare symptoms, sneezing or itchy, runny nose or allergic eye symptoms.
Cromolyn: Nasalcrom nose spray, Opticrom eye drops
Nedocromil: Alocril eye drops, Tilade asthma prevention inhaler
Medication in this group is taken by mouth and works to prevent allergic inflammation.
Common Side Effects: Flu-like symptoms such as headache, congestion, abdominal pain or nausea, nervousness, anxiety or aggressive behavior, depression, insomnia, allergic rash.
Precautions: Do not take this medication if you have significant depression or anxiety, because it could worsen your symptoms.
DrugsThat Treat Allergy Symptoms
These drugs relieve nasal congestion by shrinking swollen nasal tissues. Most are available without a prescription, as tablets, syrups and nasal sprays. Some of these drugs are combined with an antihistamine.
Nonprescription: Phenylephrine, oxymetazoline and pseudoephedrine, available as single ingredient and combination products, generic and brand names, in tablet, capsule and syrup forms; also found in some prescription combination products. In some states, pseudoephedrine tablets require a prescription.
Common Side Effects: Nervousness, restlessness, insomnia. Nasal sprays can dry or irritate the nose.
Precautions: Consult your doctor before using oral decongestants if you are taking antidepressants or have high blood pressure, diabetes or heart disease.Long-term use of nonprescription decongestant nasal sprays can lead to a rebound effect in which the drug stops working and symptoms return, worse than before. For this reason, decongestant sprays should not be used for longer than three days.
These combination drugs work on two fronts: They block the action of histamine and relieve nasal congestion, sneezing and other allergy symptoms. Many are available without a prescription.