Zyrtec is an antihistamine that relieves allergy symptoms, such as a runny nose or itchy, watery eyes. It works by blocking the body’s histamine receptors, explains Cleveland Clinic. It is one of the second generation antihistamines that are thought to be safer than first generation antihistamines (such as Benadryl). Like other antihistamines, it can cause side effects. Some of these include stomach aches, irritability in small children, and headache. It’s important to consult with a doctor before taking it, and follow the dosage instructions carefully.
Allergy medications like Zyrtec and Claritin block histamine responses, dulling the immune system’s reaction to minor or harmless allergens, explains WebMD. The drug also may decrease the effectiveness of skin prick tests for allergies, so it should be avoided at least 72 hours before the test. It can also increase the risk of seizures in people with seizure disorders, and should be used cautiously by those with kidney disease or liver problems.
The exact timeline of how soon does zyrtec work varies from person to person, as there are various factors that can affect the effectiveness of the medication, such as the individual’s age and the form it comes in. According to NHS, it takes about an hour for Zyrtec to begin working once ingested and the effects last up to 24 hours. The medicine can be taken on an empty or full stomach and does not need to be mixed with food. It’s recommended to chew the chewable tablet before swallowing and to remove an orally dissolving tablet from the blister pack with dry hands only when it is ready for use. Liquid medicine should be measured carefully with a medication measuring device or spoon rather than a kitchen spoon to avoid mistakes.