Pharmacokinetic and Pharmacodynamic Herb-Drug Interactions of Common Over-the-Counter Pain Medications.

Pain is one of the most common reasons for seeking medical intervention, and self-medication with over-the-counter medications and/or traditional herbal remedies has become increasingly popular. In this review, original articles on understanding possible herb-drug interaction between traditional herbs and four major pain medication: acetaminophen, aspirin, ibuprofen, and naproxen were compiled and analyzed. In terms of analytical methods, high-performance liquid chromatography using an isocratic eluent system coupled to biological sample clean-up is the most common, while a wide variety of detectors have been observed, including a photo diode array, variable wavelength detector, electrochemical detector, and tandem mass spectrometer. Both synergistic and anti-synergistic effects were observed for acetaminophen and aspirin, while only synergistic effects have been found for naproxen. Currently, no interactions have been reported for ibuprofen.