Best Allergy Medications 2026: Zyrtec vs Claritin vs Allegra vs Xyzal

March 15, 2026 · 10 min read

Written by the drug-price.info Editorial Team
Reviewed using FDA-approved drug labels and clinical pharmacology references. Information is for educational purposes only and is not a substitute for professional medical advice.

Allergy season is here, and the antihistamine aisle can be overwhelming. The four most popular over-the-counter allergy medications — Zyrtec (cetirizine), Claritin (loratadine), Allegra (fexofenadine), and Xyzal (levocetirizine) — are all second-generation antihistamines, but they differ in important ways.

We break down the pros, cons, drowsiness levels, onset time, duration, and cost so you can pick the right one for your allergies.

Quick Comparison Table

Feature	Zyrtec	Claritin	Allegra	Xyzal
Generic name	Cetirizine	Loratadine	Fexofenadine	Levocetirizine
Onset time	~1 hour	1–3 hours	~1 hour	~1 hour
Duration	24 hours	24 hours	12–24 hours	24 hours
Drowsiness risk	Moderate	Low	Lowest	Moderate
Strength	Strong	Moderate	Moderate	Strongest
Best for	Severe allergies, hives	Mild-moderate allergies	People needing alertness	Severe/nighttime allergies
Brand 30-ct price	~$18–22	~$18–22	~$18–24	~$20–25
Generic 30-ct price	~$4–8	~$4–8	~$5–10	~$6–10
Age (OTC)	2+ years	2+ years	2+ years	6+ years

Zyrtec (Cetirizine): Best for Severe Allergies

Cetirizine is one of the most effective OTC antihistamines. It works fast — usually within an hour — and provides strong 24-hour relief. Multiple studies rank it as more potent than loratadine for controlling symptoms like sneezing, runny nose, and itchy eyes.

Pros

Fast onset (~1 hour) with strong symptom relief
Particularly effective for hives (urticaria)
24-hour coverage with a single dose
Very affordable as a generic ($4–8 for 30 tablets)
Available for children 2 and older

Cons

Most likely of the four to cause drowsiness (~10–14% of users)
Some people report a "foggy" feeling
May impair driving in sensitive individuals

Best for: People with moderate-to-severe allergies who can tolerate mild drowsiness, or who take their dose at bedtime.

Claritin (Loratadine): Best Non-Drowsy All-Rounder

Loratadine is the classic "non-drowsy" antihistamine. It causes drowsiness in only about 2–3% of users — barely above placebo. The trade-off is that it's generally considered slightly less potent than cetirizine, and it takes longer to reach peak effect (1–3 hours).

Pros

Truly non-drowsy for the vast majority of people
No significant impact on driving or cognitive function
24-hour coverage
Widely available and very affordable as generic
Available for children 2 and older

Cons

Slower onset (1–3 hours to peak effect)
Less effective than cetirizine for severe symptoms
May not fully control heavy nasal congestion

Best for: Mild-to-moderate allergies where staying alert and functional during the day is a top priority.

Allegra (Fexofenadine): Least Drowsy Option

Fexofenadine is the least sedating antihistamine available. Clinical studies show its drowsiness rate is essentially the same as a sugar pill. It's the go-to choice for pilots, truck drivers, and anyone who cannot afford any sedation risk.

Pros

Virtually zero drowsiness — FDA doesn't require a sedation warning
Fast onset (~1 hour)
No impairment of driving or complex task performance
Does not cross the blood-brain barrier significantly

Cons

Some formulations only last 12 hours (need twice-daily dosing)
Generally considered less potent than cetirizine or levocetirizine
Grapefruit, orange, and apple juice can reduce absorption by up to 36%
Slightly more expensive as a generic

Important: Do not take Allegra with fruit juice. Grapefruit, orange, and apple juice interfere with absorption. Take it with water only, and wait at least 4 hours before or after drinking juice.

Best for: People who need maximum alertness — professionals, students, drivers — or anyone sensitive to even mild sedation.

Xyzal (Levocetirizine): Strongest Antihistamine

Levocetirizine is the active form (R-enantiomer) of cetirizine. It's considered the most potent OTC antihistamine available, providing the strongest H1-receptor blockade. It's particularly effective for severe allergy sufferers and chronic hives.

Pros

Most potent antihistamine per milligram
Fast onset (~1 hour) with full 24-hour coverage
Excellent for chronic hives (urticaria)
Half the dose of cetirizine (5mg vs 10mg) for equivalent effect

Cons

Drowsiness risk similar to cetirizine (~6%)
OTC approval only for ages 6+ (prescription needed for younger children)
Slightly more expensive than cetirizine generic
May cause fatigue in the first few days

Best for: Severe allergy sufferers who need maximum symptom control, or those with chronic hives who haven't found relief with other antihistamines.

Drowsiness Comparison: Side by Side

Medication	Drowsiness Rate	Sedation Level	Best Time to Take
Allegra	~1–3%	None (same as placebo)	Morning
Claritin	~2–3%	Minimal	Morning
Zyrtec	~10–14%	Mild–Moderate	Bedtime
Xyzal	~6%	Mild	Bedtime

Which Should You Choose?

There's no single "best" allergy medication — it depends on your priorities:

Need to stay sharp? Choose Allegra — virtually zero sedation risk.
Want reliable non-drowsy relief? Claritin is the proven daily all-rounder.
Have severe allergies? Zyrtec hits harder — take it at bedtime to sleep through the drowsiness.
Nothing else working? Xyzal is the most potent option for stubborn symptoms and chronic hives.

Can You Combine Antihistamines?

Do not take two antihistamines at the same time unless directed by a doctor. Doubling up increases drowsiness and side effect risk without proportionally improving symptom relief.

If one antihistamine isn't enough, talk to your doctor about adding a nasal corticosteroid spray like fluticasone (Flonase) or an eye drop like ketotifen (Zaditor) — these treat different parts of the allergic response and can safely be used together with an oral antihistamine.

Tips for Getting the Most From Your Allergy Medication

Start early: Begin taking your antihistamine 1–2 weeks before allergy season peaks for best results
Take it consistently: Daily use is more effective than "as needed" for seasonal allergies
Try the generic: Generic cetirizine, loratadine, and fexofenadine are identical to brand names at a fraction of the cost
Time it right: Take Zyrtec or Xyzal at bedtime; Claritin or Allegra in the morning
Add a nasal spray: Combining an oral antihistamine with a nasal corticosteroid provides the most complete relief

Save money: All four of these medications are available as generics. Check our guide to the cheapest allergy medicines for pricing comparisons and where to get the best deals.

Medical Disclaimer: This article is for informational purposes only and is based on FDA drug label information and published clinical studies. Never stop, start, or change medications without consulting your healthcare provider. If you think you may have a medical emergency, call your doctor or 911 immediately. Drug-price.info does not provide medical advice, diagnosis, or treatment.