Can You Take Zyrtec And Xyzal Together?

Answer

Thanks so much for contacting us! No, you don't want to combine Zyrtec (cetirizine) and Xyzal (levocetirizine) together. They are both very similar antihistamines and taking both together will generally not result in any additional benefit and only increase the risk of side effects occurring (such as dizziness, drowsiness, and dry mouth).

If you are finding that one antihistamine isn't working well enough for you to relieve your allergy symptoms, you can have some options that I will discuss in the sections below (such as adding on a nasal steroid, like Flonase).

How Are Zyrtec & Xyzal Different?

Zyrtec contains cetirizine and Xyzal contains levocetirizine. You'll notice the similarity in these drug names.

Many drugs are made up of molecules that can exist in two forms that are mirror images of each other, just like our left and right hands. These mirror-image molecules are called enantiomers, and they can have different effects on the body.

In some cases, only one enantiomer may be responsible for the therapeutic effects of the drug, while the other enantiomer may have little or no activity or even cause harmful side effects.

Many medicines are made up of both versions of a molecule, but some are only made up of one version. For example, Nexium is a proton pump inhibitor containing esomeprazole. It is the 'left-handed' enantiomer (i.e., isomer) of omeprazole (Prilosec).

As mentioned, Zyrtec contains cetirizine, which actually is a combination of:

• Dextrocetirizine, the right-handed molecule
• Levocetirizine, the left-handed molecule 

While both molecules have similar chemical structures, they have different spatial arrangements of atoms (are mirror images of each other), which results in differences in how they interact with histamine receptors in your body.

Studies show that levocetirizine is responsible for the antihistamine effects of cetirizine, while dextrocetirizine is thought to have little to no activity.

All of this is to say that Xyzal (levocetirizine) is the active enantiomer of Zyrtec (cetirizine) and has similar effects to cetirizine, but at a dosage that is approximately half as much.

This is why an adult dose of Zyrtec is 10 mg per day, while for Xyzal, it is 5 mg per day.

Zyrtec & Xyzal Shouldn't Be Combined

By taking Zyrtec and Xyzal together, you would essentially be taking a double dose of antihistamines. It would be like taking two doses of Zyrtec (since, as mentioned above, one 5 mg dose of Xyzal is essentially equivalent to one 10mg dose of Zyrtec).

While some studies report that certain individuals may receive some benefit by taking higher doses of Zyrtec (more than the recommended maximum daily dose), this generally isn't recommended.

Higher doses of antihistamines generally don't produce much more of a clinical effect than simply sticking to the recommended dose and can put you are greater risk for side effects.

With Zyrtec/Xyzal, these side effects would include:

• Dizziness
• Sedation
• Dry Mouth
• Constipation
• Dry eyes

Alternative Options - Try A Nasal Steroid

I imagine you are writing to us because one dose of Zyrtec/Xyzal hasn't been working well enough for you.

I highly recommend you consider either a nasal steroid or a nasal antihistamine.

Countless studies have found, that for most individuals, nasal steroids are more effective at treating allergy symptoms than oral antihistamines.

Nasal steroids available over the counter include:

• Flonase
• Rhinocort
• Nasacort AQ

Additionally, you can combine an oral antihistamine, like Zyrtec, with a nasal steroid, like Flonase, and studies show the combination is more effective than either alone.

Nasal antihistamines are also an option for you. Astepro, which is available over the counter, contains azelastine and is effective at trying allergy symptoms, sometimes more so than an oral antihistamine. Nasal antihistamines, like oral, can also be used with a nasal steroid for even greater relief.

Final Words

Thanks so much again for contacting us!

I hope you found this answer helpful!