Americans spend more than $2 billion annually on non-prescription pain relievers. Today we'll find out what they are, how they work, how they differ from one another and from prescription drugs, what side effects they cause, and more. Rear Admiral Sandra Kweder, MD, deputy director of the Food and Drug Administration's Office of New Drugs, is here to answer your questions on aspirin, ibuprofen, acetaminophen, and all the rest.

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