I accidentally overdosed on loratadine. What can I do?

Nothing. Claritin (loratadine) and most other nonsedating third generation antihistamines are very safe. The initial studies for Claritin (loratadine) were done at 40 mg (4 times the currently recommended dose). If a physical symptom is experienced after using any medication at an excessively high dose, the best resource is the "poison control" center. They are available 24/7 by calling 1-800-poison1.
Overdosed. If you overdosed, call 911 immediately and get to the emergency room. If you simply took two or three pills, the main side effect is drowsiness. Do not drink alcohol with loratadine.