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Decongestant Vs. Antihistamine

Few people escape the pain and inconvenience of upper respiratory ailments caused by allergies, a cold, a sinus infection or a change in the weather. Most people go to their local drugstore or pharmacy and purchase over-the-counter (OTC) medication to open sinus passages and gain some relief. Because the symptoms vary in degree and origin, it helps to understand whether you need a decongestant or antihistamine.

  1. Upper Respiratory System

    • The upper respiratory system includes the nose, mouth and throat area. In general, complaints include a stuffy or runny nose, sneezing, coughing, sore throat and inflammation of the tissue and blood vessels. Swollen blood vessels in the nasal cavity cause congestion or a stuffy nose by preventing the flow of air and fluid through the system. Histamine, a body chemical, triggers a stuffy or runny nose, congestion, sneezing and itchy eyes that accompany allergies or infection.

    Decongestants

    • Common decongestants include pseudoephedrine and phenylephrine and come in pill or spray form. They shrink swollen blood vessels in the nasal passage, reducing blood flow and allowing air to pass through more easily. Decongestants are related to adrenalin, with side effects that include increased heart rate, high blood pressure and difficulty falling asleep. People with heart conditions, high blood pressure, diabetes and thyroid disease should consult a doctor before using decongestants. Do not use a decongestant if you have used an MAO inhibitor in the previous 14 days.

    Antihistamines

    • Antihistamines target histamine activity in your system, blocking it from receptors that cause the symptoms. First-generation antihistamines---containing brompheniramine, chlorpheniramine, dimenhydrinate, diphenhydramine or doxylamine---often cause drowsiness and dry mouth. Second-generation antihistamines made from loratadine come in non-drowsy formulas.

    Precautions

    • Do not take either mediation for too long. Decongestants can overdry your nasal cavity and cause more congestion for a few days once you stop taking them. Use nasal sprays for immediate relief and acute situations for no more than three days in a row. Antihistamines do not prevent the production of histamine and therefore only provide temporary relief. As with any medication, consult your doctor if you have pre-existing medical conditions or concerns.

    Pseudophedrine at the Counter

    • The Methamphetamine Anti-Proliferation Act limits your purchase of pseudoephedrine, a level-I narcotic used in methamphetamine production. The act also requires you fill out a form at the pharmacy in order to purchase it. The purpose is to monitor purchases for amounts that exceed the bill's threshold of "9 gram single transactions with the package size not to exceed 3 grams."

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