Pain of multiple etiologies remains a substantial problem for many patients presenting in the clinical setting. Improved pain relief can be demonstrated, and adverse effects minimized, by multimodal analgesic combinations as the method to improve pain treatment. Substantial evidence supports combining analgesics for the management of pain and, in some instances, they have a heterogeneous pharmacologic sparing effect. Fixed-dose combination analgesics with demonstrated efficacy and safety are widely useful for pain management. However, work needs to continue to further explore which analgesics at which doses can be combined with a coanalgesic in a patient-specific manner to achieve additive, if not synergistic, multimodal pain relief with the fewest possible adverse consequences. Unsupervised consumption of over-the-counter drugs that contain acetaminophen, aspirin, or ibuprofen offers clinical challenges to both the patient and health care providers. Couple this often undisclosed over-the-counter medication consumption event with prescription medications, which many contain similar combination ingredients, and the potential for a therapeutic misadventure may precipitate. This article will address the safety and efficacy of acetaminophen, aspirin, and ibuprofen independently and in combination with currently available prescription dosage forms with a focus on pharmacology, pharmacotherapeutics, pharmacodynamics, and pharmacokinetics, including drug interactions at the CYP450 system. Patient-specific cautions are presented for opiate/opioid combinations, codeine, hydrocodone, oxycodone, and propoxyphene, and there is a discussion of COX I/COX II agents.