Which is faster acting Zyrtec or Allegra?
Allegra works within two hours and Zyrtec works within one hour. Several studies have found cetirizine (Zyrtec) to be more effective than fexofenadine (Allegra) at relieving symptoms of allergic rhinitis and urticaria, and it appears to have a longer duration of action.
Cetirizine (Zyrtec) tends to be the most fast-acting medication — that can take effect in as little as one hour — but it also carries the highest potential for drowsiness. Loratadine (Claritin) can take up to three hours to take effect and may cause minor drowsiness.
Most people experience at least 24 hours of relief after a single dose. Zyrtec, on the other hand, is fast acting. People who take it may feel relief in as little as one hour. Antihistamines like Zyrtec and Claritin are designed to calm the histamine reaction your body has when it's exposed to an allergen.
Relieve your hay fever and allergy symptoms like runny nose, sneezing, itchy, watery eyes, itchy nose, or itchy throat. Allegra® starts working in one hour — twice as fast as Claritin* — and won't leave you feeling drowsy like Zyrtec. That is why it's the #1 allergist recommended non-drowsy allergy brand.
How long does it take for Allegra to work? Allegra Adult Allergy Medicine starts working in one hour to give you fast, non-drowsy, 24-hour relief of allergy symptoms including sneezing, runny nose, itchy watery eyes, and itchy nose or throat.
Allegra and Zyrtec are common over-the-counter drugs used to treat allergy symptoms. Both drugs are safe and effective, but studies show Zyrtec's effects may last longer than Allegra's. Zyrtec is more likely to cause drowsiness. Drinking fruit juices can make Allegra less effective.
Response and effectiveness. Peak concentrations are reached within one hour of administration of Zyrtec tablets or syrup. The onset of its effect occurs within 20 minutes in 50% of people and an hour in 95%. Effects persist for at least 24 hours following a single dose of Zyrtec.
If your allergy is particularly bad then yes you can take them on the same day, as there are no known interactions. This is a therapeutic duplication and it is usually recommended to take only one antihistamine at any time, however if you have been prescribed to take both together then it is appropriate.
Official answer. Cetirizine can be taken at any time of the day. In most people it is non-sedating, so they take it in the morning. However, a percentage of people do find it to be sedating so if it does make you drowsy it is best to take it in the evening.
Allegra: Which is best at relieving allergy symptoms? All three medications work well against allergies, but there are a few differences between them. For example, Zyrtec tends to start working slightly faster, but has a higher chance of causing drowsiness, than Claritin or Allegra.
Is it better to take Allegra in the morning or at night?
Also, if you're used to taking Allegra in the morning, try switching to a bedtime dose. You're less likely to be drinking juice that time of night, and some studies have shown that gives you peak control just when you're waking up the next morning.
Human histamine skin wheal and flare studies in adults following single and twice daily doses of 20 and 40 mg fexofenadine hydrochloride demonstrated that the drug exhibits an antihistamine effect by 1 hour, achieves maximum effect at 2 to 3 hours, and an effect is still seen at 12 hours.
When an allergy medication doesn't work anymore—either as well as before or at all—it could be because your body is no longer reacting to the drug in the same way it once did or is clearing it too quickly for it to be effective. This is known as a drug tolerance. This can happen after months and years of use.
For example, while Claritin 24-hour and Allegra 24-hour tablets are only taken once every 24 hours, Claritin 12-hour and Allegra 12-hour tablets are typically taken once every 12 hours. Benadryl is usually taken once every 4-6 hours or as directed by a doctor.
Studies point to Claritin being more effective than Allegra for allergic rhinitis (faster onset of action, more symptom relief) Allegra may provide more eye symptom relief. Studies suggest Allegra may be more effective than Claritin for wheal and flare reactions (an allergic skin reaction).
Zyrtec (cetirizine) is the strongest of the second-generation antihistamines, says Dr. Garcia-Ibáñez. And because there is less chance of toxicity with this medication, the dosage can be increased substantially, at the discretion of your doctor, he says. Zyrtec is an effective treatment for allergy symptoms and hives.
For mild to moderate allergy symptoms, Allegra may be preferable since other drugs are more sedating. Yet for severe symptoms that are interfering with work, school, or play, a medication such as Zyrtec may be needed. It all depends on how much symptom relief you need and the degree of side effects you can tolerate.
Studies have shown equal effectiveness for Zyrtec and Claritin for allergic rhinitis and urticaria. Studies have not compared the effects of Zyrtec and Claritin for conditions such as postnasal drip, but research suggests intranasal antihistamines such as azelastine are more effective.
Newer antihistamines like Allegra and Claritin are generally safe for daily use. But allergy medications with decongestants, such as Claritin-D or Benadryl-D, could make your allergies worse with long-term use.
First generation antihistamines, while very effective at controlling symptoms, are often associated with symptoms in older adults such as anxiety, confusion, sedation, blurred vision, reduced mental alertness, urinary retention and constipation.
What happens if you take Zyrtec before bed?
Take Allergy Medications at Night
Many allergy medications, such as Zyrtec, are recommended every 24 hours. By taking the medication before bedtime you're more likely to get through the night without the active ingredients wearing off or becoming less effective closer to the end of the 24 hour period.
Antihistamines can stop working because your allergies might be getting worse or you might have immune system changes due to aging. You also might not be taking the medication as directed. If you take an antihistamine after being exposed to an allergy trigger, it won't work as well.
Interactions between your drugs
No interactions were found between Allegra and Zyrtec.
Flonase® and ZYRTEC® treat allergy symptoms in different ways. ZYRTEC® is an oral antihistamine and comes in a variety of forms: liquid gels, tablets and chewable tablets. ZYRTEC® starts working at hour 1 on the first day you take it. Flonase® is a steroid nasal spray and works differently.
“It works longer than you might suspect,” says May. And because the two drugs work so similarly, if you take a Zyrtec plus an Allegra in one 24-hour period, you're getting more than the recommended amount without any additional benefit. “It's no different than taking two Zyrtec,” Hill says.