Zyrtec vs. Allegra
See how Zyrtec and Allegra compare on approved uses, dosing, side effects, and cost.
Key Takeaways
Zyrtec and Allegra are both second-generation antihistamines approved for allergic rhinitis and chronic hives, taken once daily by most adults.
Zyrtec causes more drowsiness than Allegra, with somnolence reported in up to 14% of users compared to Allegra's non-sedating profile.
Allegra offers more dosing flexibility with once- or twice-daily options, while Zyrtec sticks to a single once-daily dose across all strengths.
Zyrtec vs. Allegra Drug Summary
Zyrtec
Zyrtec (cetirizine) is a second-generation antihistamine used to relieve seasonal and year-round allergy symptoms and chronic hives. It works by blocking histamine receptors and is taken once daily as a tablet, chewable, capsule, or oral solution. It is available over the counter and as a generic.
Allegra
Allegra (fexofenadine) is a second-generation antihistamine used to relieve seasonal allergy symptoms and chronic hives. It is taken once or twice daily depending on the dose, and comes as a tablet, orally disintegrating tablet, or oral suspension. It is available over the counter and as a generic.
Zyrtec vs. Allegra Side Effects
Zyrtec
Allegra
Zyrtec vs. Allegra Dosage
Zyrtec
Allegra
| STAGE | DOSE | WHEN |
| Starting dose | 2.5 mg once daily | At the start |
| Maximum dose | 10 mg once daily | If needed |
| Dose changes | 2 increases | As tolerated |
| STAGE | DOSE | WHEN |
| Starting dose | 30 mg twice daily | At the start |
| Maximum dose | 60 mg once daily | If needed |
| Dose changes | 3 increases | As tolerated |
Zyrtec
| STAGE | DOSE | WHEN |
| Starting dose | 2.5 mg once daily | At the start |
| Maximum dose | 10 mg once daily | If needed |
| Dose changes | 2 increases | As tolerated |
Allegra
| STAGE | DOSE | WHEN |
| Starting dose | 30 mg twice daily | At the start |
| Maximum dose | 60 mg once daily | If needed |
| Dose changes | 3 increases | As tolerated |
Zyrtec vs. Allegra Indications
Zyrtec
Zyrtec is FDA-approved to relieve symptoms of seasonal and year-round allergic rhinitis, such as sneezing, runny nose, and itchy eyes. It is also approved to treat chronic idiopathic urticaria, an ongoing hives condition with no known cause.
Seasonal allergic rhinitis
Perennial (year-round) allergic rhinitis
Chronic idiopathic urticaria (hives)
Allegra
Allegra is FDA-approved to relieve symptoms of seasonal allergic rhinitis, including sneezing and nasal congestion. It is also approved to treat chronic idiopathic urticaria, the same type of ongoing unexplained hives that Zyrtec treats.
Seasonal allergic rhinitis
Chronic idiopathic urticaria (hives)
Approved for use in children as young as 6 years old
Zyrtec vs. Allegra Pros and Cons
Zyrtec
Zyrtec works quickly and covers both seasonal and year-round allergy triggers, but it carries a higher chance of drowsiness than many other second-generation antihistamines. People with kidney or liver problems may need a lower dose.
Pros
Approved for year-round (perennial) allergy symptoms, not just seasonal ones
Comes in chewable tablets, syrup, and capsules for easy dosing across ages
Single once-daily dose regardless of strength needed
Cons
More likely to cause drowsiness than Allegra, up to 14% of users
Requires dose reduction in people with kidney or liver impairment
Not approved for infants under 6 months old
Allegra
Allegra is one of the least sedating antihistamines available and is metabolized minimally by the liver, which can matter for people on other medications. It offers more dosing flexibility, but that also means more strengths and schedules to keep track of.
Pros
Considered non-sedating, with less drowsiness risk than Zyrtec
Minimal liver metabolism, a plus for people on liver-cleared medications
Once-daily 180 mg option available for adults who want to dose less often
Cons
Some formulations require twice-daily dosing, which can be harder to remember
The orally disintegrating tablet contains phenylalanine, a concern for phenylketonuria
More strengths and schedules across age groups can make dosing confusing
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