What are the side effects of Zyrtec in older adults?

People 65 and older may be more susceptible to certain side effects of the second-generation antihistamine

By Sarah Bradley | Jan. 25, 2024 Medically reviewed by Karen Berger, Pharm.D.

Zyrtec (cetirizine) is one of the most commonly used over-the-counter antihistamines for treating seasonal and environmental allergies. It’s part of the second generation of antihistamines developed after medications like Benadryl (diphenhydramine) and Dramamine (dimenhydrinate). It works just as well against allergies but with less sedating side effects.

However, one group of people is more likely to experience side effects from Zyrtec: older adults, or people 65 years and older. For this age group, even second-generation antihistamines can cause excessive fatigue and sleepiness, which could lead to other problems, like accidental falls and injury. This happens because your metabolism slows down as you age, a change that increases your sensitivity to medications, says Nishant Reddy, MD, a board-certified otolaryngologist with NJ ENT & Facial Plastic Surgery in New Jersey.

Does this mean you can’t take Zyrtec if you’re 65 or older? For some people, yes—but not for everyone. Here is what you should know about Zyrtec side effects in older adults.

Zyrtec side effects in elderly users

First-generation antihistamines, such as Benadryl and Dramamine, are generally not recommended for use in older adults because they can cause a range of side effects, reports the American Academy of Allergy, Asthma & Immunology (AAAAI), including:

Fatigue and drowsiness
Anxiety
Confusion and decreased alertness
Blurred vision
Urinary retention, or difficulty urinating
Constipation

These drugs cross the blood-brain barrier, which means they may cause more intense side effects or adverse reactions, especially in the elderly population, and are also more likely to interact with other common prescription and OTC medications.

But second-generation antihistamines, like Zyrtec, are less likely to cause these side effects for older adults, notes the AAAAI. Zyrtec is one of the antihistamines more commonly used in this age group; however, safety data is lacking for older adults, according to Drugs & Aging. Zyrtec carries some risk of mild side effects for everyone, such as:

Tiredness
Sore throat
Dizziness
Headache
Dry mouth

Serious side effects and risks for older adults

Less commonly, Zyrtec carries a risk of more serious side effects, including anemia, anaphylaxis, hepatitis, and low platelet count.

Many of the serious side effects that can occur in older adults taking Zyrtec involve other health conditions or medications. Older adults with cardiovascular disease, urinary retention, or increased ocular pressure (i.e., glaucoma) should not take any antihistamines, including second-generation ones, says Jared Braunstein, DO, an internist with Medical Offices of Manhattan in New York, New York.

Because Zyrtec is processed in the kidneys, people with any type of kidney or renal disease should talk to a healthcare professional before taking Zyrtec; people with liver disease are advised to do the same as Zyrtec may, in rare cases, increase levels of liver enzymes.

Finally, some medications and substances should not be combined with Zyrtec, especially in the geriatric population, because of potential drug interactions. Dr. Reddy says this includes alcohol, certain nervous system depressants (such as benzodiazepines for anxiety or sedatives used for sleep), and opioid pain relievers. You may also need to avoid combining Zyrtec with gabapentin, some narcolepsy drugs, and some calcium channel blockers (like verapamil).

Managing Zyrtec side effects in the elderly

Unless your healthcare provider recommends avoiding Zyrtec because of other health conditions or medications, you can likely take it. If you experience mild side effects, there may be ways to minimize them, like staying hydrated if you have dry mouth, says Dr. Reddy.

For the most common side effect of drowsiness or fatigue? There’s a fix for that, too: “I would recommend an elderly patient take second-generation antihistamines [like Zyrtec] at bedtime,” says Dr. Braunstein. This way, if it makes you slightly drowsy, it won’t interfere with your daily activities.

However, Dr. Braunstein adds that experiencing urinary retention or blurred vision is a warning sign that you should stop taking Zyrtec and seek medical attention.

Alternatives for allergy relief in older adults

Although Zyrtec is generally considered safe for most older adults, it may not be an option for you. That doesn’t mean you have to live with allergy symptoms, though—there are other allergy medicines you can use.

Intranasal steroids (nasal sprays like Flonase and Nasacort) are typically safe for people older than 65 and are one of the most common alternatives to oral antihistamines.

You may also be able to take an intranasal antihistamine like Astepro (azelastine). “Moving to an intranasal antihistamine can sometimes provide similar effects of an oral medication without the systemic side effects,” Dr. Reddy says.

Antileukotrienes, like Singulair (montelukast sodium), are also considered safe and effective, especially for seasonal allergies, according to Drugs & Aging.

Finally, intranasal anticholinergics may be an option for you as well; the most common of these is ipratropium bromide, which works especially well for treating a runny nose.

If you would like to treat your allergies naturally, without prescription or OTC allergy medications, there are a few strategies you can try:

Avoiding your triggers and reducing your exposure to known allergens is one of the easiest ways to alleviate your symptoms.
Using nasal irrigation with saline can flush out irritants and keep sinus passages from drying out.
Taking probiotics can help support a healthy gastrointestinal system, which can also boost your immune system and allergic response.
Running a dehumidifier or an air purifier in your home can keep air from becoming too dry and remove excess allergens.
Some people find relief from allergy symptoms by trying acupuncture, a suggestion that seems odd but has some real science behind it.
Try using certain vitamins and supplements, like stinging nettle and quercetin, according to the Cleveland Clinic. They may decrease your symptoms, but there isn’t much scientific evidence for their use. Just be sure to talk to your provider before taking any OTC supplement to ensure it’s safe for you.

The bottom line: Most seniors can safely take Zyrtec

In general, many older people can safely take Zyrtec. Because it’s a second-generation antihistamine, it’s less likely to cause sedating side effects than drugs like Benadryl. However, some people should not take Zyrtec, and older adults should be on the lookout for serious side effects like urinary retention and blurred vision.

It’s always a good idea to talk to your healthcare provider if you are older than 65 and have seasonal or environmental allergies. Your provider can tell you if Zyrtec is safe for you to take based on your other health conditions and medications and help you find an alternative medication to treat your allergies if needed.