We may not know much about allergies, but gosh darn it do we have some great drugs for them. In the United States, the allergy aisle in a typical pharmacy is a veritable Baskin Robbins of drug options. Nasal sprays. 24-hour non-drowsy pills. Sleep-inducing, decongesting, grape-flavored serums. We’ve got it all.
But how do you choose? Ask your friends, and you’ll probably get five different recommendations on which is absolutely the best. And unfortunately for you, they’re all correct.
“Figuring out which medications are right for you is like trying to navigate a complex roadmap for a long road trip,” says Sarena Sawlani, Medical Director at Chicago Allergy and Asthma. “There usually isn’t a ‘one size fits all’ approach.”
Different pills work for different people… we’re just not sure why
Antihistamines aren’t all created equal—but it’s pretty close. The pills labeled as such in the allergy aisle all work on the same basic principle:
Allergy symptoms are caused by your body reacting to irritants like pollen or pet dander and releasing large quantities of a chemical called histamine. Histamine expands your blood vessels and increases mucus production, among other things, by attaching to receptors on the cells in your nose and sinuses. Antihistamines work because they look kind of like histamine, and can therefore bind to histamine receptors—except better.
The only real differences between pills like Allegra (fexofenadine), Zyrtec (cetirizine), and Claritin (loratadine) are how the body metabolizes them. Loratadine gets processed a lot by your liver, whereas cetirizine and fexofenadine don’t as much. This shouldn’t have an effect on how well they bind to histamine receptors, but depending on your personal metabolism and liver, it may change the side effects.
Some of the antihistamines also work a bit better on rashes and other skin symptoms. Cetirizine and fexofenadine tend to accumulate more in your skin tissue, so they have a slightly higher impact on the histamine receptors there than loratadine does. But again—your mileage may vary.
But nasal sprays definitely seem to work better
The one thing that holds clear across all the drug options is that corticosteroids seem to work the best. Corticosteroids are the active ingredient in those nasal sprays you see, and though they take longer to become fully effective, they control symptoms better in the long-term.
Pro tip: try combining an antihistamine and a corticosteroid. Since they work through slightly different mechanisms, the combination could help get rid of those last few pesky symptoms. Though as Sawlani noted, different combinations will work better for some people and not for others, so expect some trial and error.
What you think will work probably will
It’s also important to point out here that the placebo effect is quite strong for all things allergy-related. Studies of allergy treatments all have to contend with this issue, and one notable study found that the placebo effect holds even if you tell people they’re taking a placebo. Their symptoms will decrease anyway.
