What is the loratadine maximum dosage?

Why ?: Studies during development showed that the body was very tolerant to loratadine, with no significant side effects at twice the recommended dosage. However, they also found that there was no increased benefit with twice the dosage over the normal dose. Why take more if there is no benefit ?

It depends-: The full adult dose of Loratadine in other parts of the world is 20 mg. That was the most effective dose. This amount caused a 12-14% drowsiness rate. This was not acceptable for marketing in the USA. The 10 mg dose was tested against Chlorpheniramine in order to find a non-drowsy dose and it worked. So for most 10 mg is fine. Worse allergy, 20mg would help and a few will develop drowsiness.