Allegra vs Zyrtec: A Pharmacist’s Opinion

Summary: There isn’t a lot of evidence comparing Allegra vs. Zyrtec. Instead, my recommendation is based on personal experience. Zyrtec is often reported to be more effective but sometimes causes more drowsiness. The generic of Zyrtec (cetirizine) is much cheaper than generic Allegra.

Dear Curtis: I’ve tried Claritin before for my allergies and it worked OK but I thought one of the other brands might work a bit better. The two main ones I’m seeing are Allegra and then Zyrtec. What do you think about them? Is one better than the other?

One important point first: there really haven’t been any well designed clinical studies comparing these two drugs (or any of the later generation anti-histamines to each other). If there have been studies they’ve been very short term.

With that being said I’ve gotten a lot of feedback over the years from users of both of these drugs. As I’ve said before, real world feedback from users is some of the best evidence you can have.

If I had to pick between Allegra or Zyrtec I’d pick Zyrtec every time. Scratch that – I’d probably pick generic Zyrtec – Cetirizine – every time because it’s so much cheaper than the brand name.

Why Zyrtec?

Again, most of my recommendation is based purely on effectiveness. And Zyrtec just seems to be more effective overall. Especially for seasonal allergies which is why most people take either of these medications.

And it’s always been surprising to me that people have reported these differences. After all, both of these drugs are in the same class of medications and basically act in the same way. So I really can’t tell you why people report better results with cetirizine – but they do.

Safety and Side Effect Profile

Personally, the anithistamine in this group which is generally reported as having the least amount of side effects – especially sleepiness – was the one you had already tried: Claritin.

In my experience, if there is a knock on Zyrtec it’s because it causes drowsiness in some folks. So, I’d probably give a slight edge to Allegra in the side effect category.


Generic Zyrtec blows Allegra away as far as cost is concerned. I really don’t know why there is such a difference. Allegra over the counter is even more expensive than prescription Allegra. But, if cost is a concern to you then cetirizine is the way to go. Even if cost isn’t a concern to you Allegra simply doesn’t have the track record to justify paying many multiples of what you’d pay for cetirizine.


Please remember, if you ask around enough you’ll likely get a lot of different answers when comparing Allegra and Zyrtec. But the bottom line for me is I’ve just had a lot better results recommending Zyrtec to folks over the years. In fact, the one time I had to use one of these antihistamines my choice was Zyrtec.

I do have a number of folks who prefer Allegra. Again, sometimes people simply respond better to certain medications. But, considering how much cheaper generic Zyrtec is I just don’t think you’ll go wrong giving it a shot.

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