Over-the-counter painkillers containing ibuprofen and aspirin are nonsteroidal anti-inflammatory drugs that are blood thinners, according to Cleveland Clinic. They are usually safe and effective when used correctly and in moderation, but NSAIDs should not be taken with anticoagulants.
Ibuprofen and aspirin are the primary painkilling agents in brands such as Advil, Aleve, Excedrin and Motrin, states the Cleveland Clinic. Major bleeding can occur if NSAIDs are used in conjunction with anticoagulants, such as warfarin. Over-the-counter painkillers that contain acetaminophen, such as Tylenol, do not contain blood thinning agents and are safe to use with anticoagulants or if a doctor advises not to take blood thinning drugs.