If Zyrtec doesn’t work what should I try?

In this article:

• Why is Zyrtec not working?
• What to do when Zyrtec stops working
• Do people develop resistance to allergy medications?
• Can you increase your Zyrtec dosage?
• The bottom line

In this article

• Why is Zyrtec not working?
• What to do when Zyrtec stops working
• Do people develop resistance to allergy medications?
• Can you increase your Zyrtec dosage?
• The bottom line

Zyrtec (cetirizine) is an over-the-counter (OTC) medication and antihistamine used to treat allergy symptoms.

Signs of allergic rhinitis, hay fever, and seasonal allergies include sneezing, runny nose, stuffy nose, swollen nasal passages, itchy eyes, and watery eyes. These conditions are similar to nonallergic rhinitis in that they cause the same symptoms, but they are different in that the latter isn’t caused by contact with an allergen. Rather, it’s caused by other factors, such as a virus or irritants.

Zyrtec (and other allergy medicines) may not be able to fully treat those symptoms for several reasons; other treatment options may be needed.

Why is Zyrtec not working?

First, it may help to explain how the immune system responds to allergens. Basically, when it recognizes an allergen, it releases histamines, the chemical that causes allergy symptoms.

Allergy medicines such as Zyrtec may not effectively treat allergy symptoms for various reasons: It’s peak allergy season, a person’s allergies are changing, their symptoms are actually a side effect, or they have a medication tolerance.

When people take Zyrtec matters, too. “Antihistamines, like Zyrtec, have been shown to be the most effective if taken at least one to two hours before exposure to allergens,” says Dr. Luke Hentrich, Pharm.D., BCPS, an assistant professor with the department of clinical pharmacy and translational science at the University of Tennessee Health Science Center.

He says symptoms may begin as late as three to five hours after exposure and peak as late as 12 to 24 hours after. This could also make a person believe their Zyrtec isn’t working, which explains why it’s helpful to take antihistamines preemptively.

People may also want to take Zyrtec at night since it can cause drowsiness.

Additionally, allergy symptoms are not always histamine-related (back to nonallergic rhinitis). “Exposure to pollution, smoke, cleaning, or fragrance chemicals, for example, can cause similar symptoms to allergies, but the release of histamine is not involved,” says Dr. Aaron Emmel, Pharm.D., BCPS, a pharmacist and founder at Pharmacy Tech Scholar. “In these cases, taking an antihistamine will not be effective.”

According to Dr. Brian Greenberg, MD, an allergist, immunologist, and formulator for 1MD Nutrition, allergic reactions are inflammatory. While antihistamines can block histamine, he says—aka reduce itching, swelling, and redness—their benefits end there. “They do nothing for the inflammation, and that also produces many of the symptoms.”

Antihistamines can also become less helpful over time. “If used daily for more than six months, they lose their effectiveness,” Dr. Greenberg adds. (More on this ahead.)

Last but not least, antihistamines can’t work as effectively if the person taking them is still surrounded by what they’re allergic to.

“Reducing allergen exposure may increase the effectiveness of over-the-counter antihistamines, like Zyrtec,” Dr. Hentrich says. “One key nonpharmacologic recommendation in treating allergy symptoms is to identify and limit exposure to common allergens through activities like closing windows during pollen season, cleaning, dusting, doing laundry as frequently as needed, and preventing pets from being on couches and beds.”

Allergy testing can help a person determine what irritants they’re allergic to, which allows the patient to figure out avoidance strategies. An allergic reaction can be more serious; it can cause hives, swelling, chest tightness, and trouble breathing, which can be life-threatening and require emergency medical help. 

Common allergens include high pollen counts, dust mites, pet dander, stress, and changes to the environment. The presence of these can prevent Zyrtec from effectively treating allergy symptoms because, well, the allergen is still there, bothering the immune system. Being mindful of whether these are present—and if and how a person can avoid them—is key.

One of those allergens is not like the others, though: stress. How can it make allergies worse?

There are a couple of explanations. For one, experiencing allergy symptoms can be bothersome, which can exacerbate the situation (or at least make it feel that way). On the physical side, the stress hormone cortisol can increase the immune system’s response to allergens.

Stressing less—especially in the presence of allergy symptoms—is easier said than done, however. Implementing stress reduction techniques (in addition to allergy medications) is within a person’s control. Examples of the former include exercise, meditation, guided imagery, yoga, tai chi, and deep breathing exercises.

What to do when Zyrtec stops working 

When Zyrtec isn’t working, people can alleviate allergy symptoms with neti-pots, HEPA filters, knowing and avoiding allergens, and inhaling steam.

They can also try similar medications. “It is always reasonable to try other antihistamines within the same class as Zyrtec, such as Claritin, if Zyrtec is not effective,” Dr. Hentrich says. 

Other antihistamines include:

Drug name	Coupons	Learn more
Benadryl (diphenhydramine)	Diphenhydramine coupons	Learn more
Claritin (loratadine)	Loratadine coupons	Learn more
Xyzal (levocetirizine dihydrochloride)	Levocetirizine coupons	Learn more
Allegra (fexofenadine)	Fexofenadine coupons	Learn more

Each person responds to different medicines differently, so it may take some trial and error to find the best medicine for you.

He also suggests talking to a doctor or pharmacist about intranasal corticosteroids, such as Flonase (fluticasone), intranasal antihistamines, or nasal or oral decongestants such as Sudafed (pseudoephedrine) that can directly benefit specific symptoms.

Dr. Greenberg believes the best option is to use anti-inflammatory medications, like nasal steroids, routinely, then antihistamines on an as-needed basis. He says anti-inflammatory medications take longer to work but do work well, while antihistamine tolerance can be built.

Dr. Emmel recommends following up with a healthcare provider and investigating differential diagnoses. Testing may be needed to determine what’s driving the symptoms.

“This may identify an opportunity to avoid allergen exposure and manage symptoms without pharmacologic treatment,” he says. (AKA, washing bedding, HEPA filters, limiting time outdoors, etc.)

“If symptoms persist despite this, patients may benefit from switching antihistamines or adding therapies such as intranasal corticosteroids, leukotriene modifiers, and/or immunotherapy,” Dr. Emmel adds.

If the best treatment plan for allergy relief includes changing to another OTC allergy med, several are available: Benadryl (diphenhydramine), Allegra (fexofenadine), or Claritin (loratadine). Other treatment options include eye drops, decongestants, steroid nasal sprays, different kinds of nasal sprays, and allergy shots.

But again, the best bet involves a consultation with a healthcare provider for individualized treatment options.

Do people develop resistance to allergy medications?

Can taking too much medicine be a problem, causing the development of antihistamine resistance? 

Dr. Emmel wouldn’t call it “resistance,” per se, but more of a “tolerance” that can arise over time.

“This doesn’t happen in all patients, and time to tolerance varies,” he adds. “If tolerance does occur, patients can try switching antihistamines or moving to a non-antihistamine based treatment.”

Dr. Hentrich agrees that some people can become tolerant to Zyrtec, in which the medicine isn’t as effective. He says it “can occur days to weeks after taking the medication each day.”

If that happens, he recommends talking to a healthcare professional about alternative medications and identifying factors that contribute to symptoms.

Can you increase your Zyrtec dosage?

Popping another Zyrtec when one isn’t cutting it can be tempting. However, taking Zyrtec twice a day or generally upping the dosage can lead to serious side effects. 

Examples include increased sedation or sleepiness, dry mouth, urinary retention, muscle weakness, dry eyes, excessive thirst, an overdose, and more. 

In other words, increasing your Zyrtec dosage is more serious than it may seem. And, as mentioned earlier, it may not even be helpful.

The bottom line

Zyrtec may not work for multiple reasons—for example, the person is surrounded by their allergens, it’s allergy season, the symptoms aren’t caused by a histamine release, and more. If Zyrtec is not effectively managing allergy symptoms, people can try other medications, such as nasal steroids and Claritin. 

Other beneficial practices include putting HEPA filters in the home, regularly washing bedding, and inhaling steam. The most beneficial option for someone is to work with their healthcare provider. Professionals can help people find the most effective, individualized allergy solution.