you're wise to ask these questions. drug interactions can be fatal so it's always a good idea to check things out before taking medications -- including over-the-counter ones. note you can always call a pharmacist to answer these questions too. most communities have a 24-hour pharmacy and pharmacists always are happy to respond to questions like yours. if the medication your daughter is taking contains only loratadine and only guaifenesin it should be ok. many products that contain guaifenesin also contain other ingredients (like acetaminophen). but in general loratadine and guaifenesin should not interact with each other since they are in different drug classifications. loratadine is an antihistamine and guaifenesin thins the mucus. obviously any person can be allergic to any ingredient in a medication so always be alert for signs of a serious allergic reaction such as hives difficulty breathing or swelling of the lips/tongue. wishing you (and your daughter) well!
my 20yr old daughter took a 24hr loratadine 10mg 9hrs ago. could she take a 12hr 1200mg guaifenesin?