A decongestant nasal spray can provide fast allergy relief.

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When you have an allergic reaction, your body traps allergens by bringing more blood to the lining of the nose. Inflammation and swelling occur. This causes more mucus production. The combination of inflammation, swelling, and mucus causes nasal congestion and limits air flow.

Decongestants relieve stuffy noses and make it easier for you to breathe by narrowing blood vessels and reducing blood flow to mucous membranes. This results in less mucus and congestion. Decongestants also help open the nasal cavity and sinuses, often within minutes.They are a relatively safe medication when used to treat nasal allergies, and they work even if you take them after you've been exposed to an allergen.

Decongestants are available both over the counter and by prescription, and there are many different types and combinations. You can even get allergy medications that are a combination of decongestants and antihistamines. If the decongestant you use doesn't work, talk to your pharmacist or doctor. There are many varieties from which to choose.

Decongestants are available as tablets, nasal sprays or drops. Nasal sprays or drops deliver medicine directly into your nose. They can provide almost instant temporary relief of the nasal congestion that develops from allergic reactions.  However, continued use can cause a stuffy nose that doesn't clear and irritate the inside of the nose.  Be careful not to overuse.

Oral decongestants take more time to reduce congestion because they have to be swallowed and absorbed by the body. They start working after about an hour or two. Decongestant tablets are the best form to use if you need allergy symptom relief for more than a few days. Tablets should not be taken by people with heart problems, diabetes, enlarged prostate, high blood pressure, or by nursing mothers or those taking beta-blockers (blood pressure and heart medication). There can also be problems with restlessness, nervousness, insomnia.

See the next page to see more common side effects of decongestants and how to use them safely.