Cetirizine: What It Is, How It Works, and What You Need to Know

When your nose won’t stop running or your eyes won’t stop itching, cetirizine, a non-drowsy antihistamine used to treat allergy symptoms like sneezing, runny nose, and hives. Also known as Zyrtec, it works by blocking histamine, the chemical your body releases during an allergic reaction. Unlike older antihistamines that make you sleepy, cetirizine is designed to keep you alert—making it a go-to for people who need relief without the afternoon crash.

It’s one of the most common OTC antihistamine, a type of medication available without a prescription to treat allergic reactions in the UK and beyond. You’ll find it next to Claritin and Allegra on pharmacy shelves, but it’s not just another option—it’s often the most effective for people with moderate to severe seasonal allergies. Studies show it starts working within an hour and lasts up to 24 hours, which is why many users stick with it long-term. But it’s not perfect. Some people still feel drowsy, especially at higher doses, and it can dry out your mouth or cause mild headaches. If you’re on other meds, like sedatives or antidepressants, check with a pharmacist first—cetirizine can interact.

It’s also used for chronic hives, a condition where your skin breaks out in itchy welts for weeks or months. Unlike occasional allergies, chronic hives don’t always have a clear trigger, but cetirizine helps calm the body’s overreaction. It’s not a cure, but it’s one of the few tools that reliably keeps symptoms under control. If you’ve tried Claritin and it didn’t help, cetirizine might be the switch you need. And because it’s available as a generic, you can get the same active ingredient for a fraction of the brand-name price.

What you won’t find in most ads is how often people misuse it. Some take double doses because they think more means faster relief. Others use it for colds, even though it doesn’t help with congestion from viruses. And while it’s safe for most adults, it’s not always right for kids under six or people with kidney problems. The key is knowing your symptoms, matching them to the right drug, and sticking to the dose on the label.

Below, you’ll find real guides on how to pick the best OTC allergy medicine, how generics compare to brand names, and how to avoid common mistakes that make relief harder to find. Whether you’re new to cetirizine or have been using it for years, these posts cut through the noise and give you what actually works.