Desloratadine vs Loratadine Dosing: Which Works Better and How Much Should You Take?

When it comes to desloratadine, a second-generation antihistamine used to treat allergies, often sold under the brand name Clarinex and loratadine, a widely used over-the-counter antihistamine best known as Claritin, the question isn’t just which one works—it’s how much you need, how fast it kicks in, and whether the extra cost is worth it. Both are non-drowsy, both block histamine, and both treat runny nose, sneezing, and itchy eyes. But they’re not the same pill in different packaging.

Desloratadine is actually the active metabolite of loratadine. That means when you take loratadine, your body turns it into desloratadine to do the work. So why not just take desloratadine directly? Because it’s stronger. A 5mg dose of desloratadine delivers the same effect as a 10mg dose of loratadine, and it lasts longer—up to 24 hours with more consistent coverage. Studies show desloratadine binds more tightly to histamine receptors, which means fewer breakthrough symptoms for some people. But that doesn’t mean it’s better for everyone. If your allergies are mild and you’re on a budget, loratadine still works fine at half the price.

Side effects are similar—both are low-risk for drowsiness compared to older antihistamines like diphenhydramine. But desloratadine has slightly less evidence of dry mouth or headache in real-world use. For kids, both are approved, but dosing changes by weight: desloratadine syrup for children 6 months to 11 years is 1.25mg or 2.5mg daily, while loratadine syrup for the same age group is 5mg daily. Seniors or people with liver issues don’t need to adjust either dose in most cases, but if you’re taking other meds, check for interactions. Desloratadine has fewer drug interactions than loratadine, which can be affected by some antibiotics and antifungals.

There’s no magic answer here. If you’ve been taking loratadine and it’s doing the job, stick with it. But if you’re still sneezing at noon or your allergies flare up before your next pill, switching to desloratadine might give you that extra edge. It’s not about being stronger—it’s about being more reliable. And when your allergies are bad, reliability matters more than brand names.

Below, you’ll find real comparisons, patient experiences, and dosing tips from people who’ve tried both—and what actually made the difference for them.