how often can i take zyrtec

February 12, 2026

You can usually take Zyrtec (cetirizine) once a day , not more often, unless a doctor specifically tells you otherwise. It is designed to last about 24 hours in most people.

Quick Scoop: How Often Can I Take Zyrtec?

For most adults and kids 6+ years:
- Typical dose: 10 mg once daily.
- Do not exceed 10 mg (one standard adult tablet) in 24 hours unless your doctor gives different instructions (for example, for severe hives under specialist care).
For adults 65+ or people with kidney or liver problems:
- Often recommended: 5 mg once daily, with a lower maximum daily dose.
For children:
- Doses and maximum frequency depend on age and weight.
- Many pediatric charts say Zyrtec is given once every 24 hours , with some options for splitting the dose (like smaller doses every 12 hours) in certain age ranges, but still not exceeding the total daily maximum.
Zyrtec-D (with pseudoephedrine):
- Typically 1 tablet every 12 hours.
- Do not take more than 2 tablets in 24 hours.

Is It Safe to Take Zyrtec More Often?

Taking Zyrtec more than once a day, or over the labeled daily maximum, can increase the risk of side effects such as:

Drowsiness or feeling sedated.
Dry mouth.
Dizziness or headache.
In more serious overdoses: agitation, rapid heartbeat, or trouble urinating.

Some allergy and dermatology specialists sometimes prescribe higher-than-label doses (for example, multiple tablets per day) for chronic hives or severe allergic conditions, but this is a doctor-managed protocol , not something to try on your own based on internet advice or forums. Online forum posts describing people taking 3–4 tablets a day are individual experiences, not general safety guidelines.

How Often Can I Take Zyrtec? (Practical Answers)

Here’s a simple way to think about it for most over-the-counter use:

“How often can I take Zyrtec?”
→ Once every 24 hours.
“Can I take it twice a day?”
→ Generally no , unless your own doctor or specialist has instructed you to.
“I took one this morning and still feel bad—can I take another tonight?”
→ The safe default is not to exceed the labeled daily maximum. Talk to a healthcare professional or pharmacist before adding an extra dose.
“Can I take extra for a big event, like an interview?”
→ Do not self-increase the dose just for an event. If your usual dose is not working, ask your doctor about options (different antihistamines, nasal sprays, or short-term prescriptions).

When to Call a Doctor or Seek Help

Contact a doctor, urgent care, or poison control right away if:

You or someone else took much more than the labeled daily dose (for example, several tablets at once when only one is recommended).
There is extreme sleepiness, confusion, agitation, fast or irregular heartbeat, or difficulty breathing.
A child took an unknown amount or more than the package directions.

If you’re unsure about your exact dose (age, weight, kidney or liver issues, or other meds), a quick call to a pharmacist or doctor is the safest move.

Bottom Line (TL;DR)

Zyrtec is usually taken once daily , and you shouldn’t exceed the maximum daily dose on the package unless your own doctor has told you to.
If one daily dose is not controlling your symptoms, don’t just take more often—ask a healthcare professional about adjusting your plan instead.

Information gathered from public forums or data available on the internet and portrayed here.