Sammie asked
How fast does Zyrtec (cetirizine) work?
Answer
Zyrtec (cetirizine) is a second generation antihistamine and is dosed once daily as it lasts for about 24 hours. However, for allergy suffers, many want to know exactly how quickly Zyrtec begins to work to reduce allergic symptoms such as sneezing, itching and congestion.
How Fast Does Zyrtec (Cetirizine) Work?
Both Zyrtec tablets and the syrup work quickly after taking by mouth. The onset of action is generally 30 minutes to 1 hour and the drug reaches maximum blood concentration in 1 hour for adults. Studies have shown that food can reduce how quickly the drug is absorbed. In fact, food increased the time to reach maximum concentration by 1.7 hours as well reduced the maximum concentrations reached in the blood by 23%. Therefore, Zyrtec should be taken on an empty stomach if you want it to work as quickly as possible.
Additional Zyrtec Information
Duration Of Action: 24 hours per dose
Half-Life (time for 50% of drug to be metabolized): 6.5 to 10 hours
Usual dose: 5 mg to 10 mg per day
Other: No accumulation of Zyrtec in the body has be noted after continuous daily administration.
