As the snow starts to melt and the flowers start to bloom, more and more people are heading to their local drugstore and wandering the allergy medication aisle, lost in a sea of long words like "antihistamine" and "pseudoephedrine." As they compare medications, there are two words that occur over and over again: antihistamine and decongestant. What's the difference? These drugs treat similar symptoms, but they're quite different.
Uses for Decongestants and Antihistamines
A decongestant is used exclusively to reduce nasal congestion. It narrows the blood vessels found in the nasal membranes, reducing inflammation and swelling as it diminishes the mucous found in the nasal lining. An antihistamine is often used for purposes in addition to colds or respiratory infections; antihistamines can be used as a sleep aid, to stop vomiting, to act as a calming agent, and to treat annoying allergy symptoms. However, antihistamines are most popularly associated with allergy symptoms; they can treat runny nose and sneezing as well as the swelling and itching associated with hives. People with extremely allergic reactions to certain elements, such as bees or pets, often keep an antihistamine close at hand for emergency purposes.
Decongestants serve a more specific purpose than antihistamines, and they are usually available over the counter in the form of pseudoephedrine and phenylephrine. The passing of the Methamphetamine Anti-Proliferation Act in 1999 made it more difficult to purchase any medication containing pseudoephedrine, a narcotic popularly used in methamphetamine production. The consumer must sign for the medication, and it's only sold in small amounts. It's a little more inconvenient, but it's been a successful deterrent for meth makers.
Antihistamines can be purchased without a prescription. These drugs are called histamine blockers, because they can effectively block the chemical produced by the body as part of an allergic reaction, which is called histamine. The prescription antihistamines can induce more drowsiness than their nonprescription counterparts. Over the counter antihistamines can be purchased in non-drowsy formulas for those who dislike the sleepy side-effect.
Side Effects of Decongestants and Antihistamines
For all the good these drugs can do, they can also produce some alarming side effects for certain people. Due to their blood vessel constricting properties, decongestants can be harmful to people who have thyroid, high blood pressure, heart disease, or glaucoma. Long-term use of a decongestant can also result in worsening nasal congestion. Antihistamines can induce dizziness and drowsiness in some people, as well as causing dry mouth and blurred vision. People with conditions such as high blood pressure, enlarged prostate, or glaucoma are discouraged from using antihistamines. Antihistamines can also be harmful to people who take sedatives, tranquilizers, or anti-depressants. Combining the drugs can cause dangerous complications to an already existing medical issue. Pregnant women should always consult their physician before using either antihistamines or decongestants.
Armed with this information, it should be easier to make a decision when faced with a wall of medications at the local pharmacy. Assess your symptoms, and you can determine whether you need an antihistamine or a decongestant.