Antihistamine or a Decongestant?

By Stephanie Watson @WatsonWriter
October 12, 2017

How to tell whether an antihistmine or a decongestant will help your symptoms, and when you should avoid these medicines entirely. 

When a cold stops up your nose and turns it into a leaky faucet, one way to release the clog and stop the drip is to take an over-the-counter antihistamine or decongestant. But be careful when using these drugs because they’re not right for everyone, and they can have side effects — some potentially serious — when used incorrectly.


During an infection or allergy attack, your body releases a chemical called histamine, which causes your nose to become congested and run. Antihistamines block the action of this chemical to relieve symptoms like a runny nose, watery eyes, and sneezing.

Some antihistamines have been around for many years. These first-generation drugs include diphenhydramine (Benadryl), chlorpheniramine (Chlor-Trimeton), and brompheniramine (Dimetane). Newer-generation antihistamines include fexofenadine (Allegra), loratadine (Claritin), and cetirizine (Zyrtec).

What’s the difference? Older antihistamines tend to cause drowsiness, which can be a problem if you need to drive a car, operate heavy machinery, or simply stay awake through a work or school day. In that case, take a newer antihistamine or save the older one for bedtime to help you sleep. 


Swollen blood vessels inside your nose cause congestion. Decongestants shrink these engorged blood vessels to help you breathe easier. They usually include the ingredients pseudoephedrine or phenylephrine, in brand names such as Drixoral, Dimetapp, Afrin, and Sudafed. Decongestants are available in pill, liquid, or spray forms.

While helping you breathe easier, decongestants can also make you feel jittery and boost your blood pressure. Decongestant-free cold relievers like Coricidin HBP are safer for people with high blood pressure. If you do take a traditional decongestant, monitor your blood pressure to make sure it stays within the range your doctor recommends. “If it increases excessively and is consistently over 140/90, then they need to speak to their doctor,” says Willie E. Lawrence, Jr., MD, chief of cardiology at Research Medical Center in Kansas City, Mo., and American Heart Association spokesperson.

Spray decongestants can become habit-forming, and they’re not recommended for more than three days. With more than three days of use, you can develop rebound congestion, putting you right back where you started.

Combo products

Some products combine an antihistamine and decongestant in one pill. Brand names include Chlor-Trimeton D, Claritin-D, Dimetapp, Drixoral, Sudafed Plus, and Tavist-D. Taking the two drugs together may help balance out the jitteriness and sleepiness they can cause individually.

Multi-symptom cold medicines contain a decongestant or antihistamine, plus ingredients to combat other cold symptoms, such as a pain reliever and cough suppressant. Though these drugs relieve multiple symptoms at once, you could end up getting medicine for symptoms you don’t have. You’re better off using an individual decongestant or antihistamine if congestion, runny nose, or sneezing is your main symptom. 

Cold medicines and kids

Antihistamines and decongestants can relieve nasal symptoms on adults and older children, but they’re not meant for kids under age 4. “Products like these may work for adults, and parents think it could help their children as well. But what’s good for adults is not always good for children,” says Matthew M. Davis, MD, MAPP, professor of pediatrics and communicable diseases at the University of Michigan. Cold medicines don’t work in young children, and they can cause serious side effects in this age group.

Because many of these drugs look like candy, keep them well out of children’s reach. Thousands of children wind up in emergency rooms each year after taking cold and cough medicines — most of them without a parent’s knowledge. 


March 30, 2020

Reviewed By:  

Janet O’Dell, RN