“…Opioids have long been marketed as combination products, initially with acetaminophen and aspirin and then with NSAIDs such as ibuprofen. Clinicians appreciate the advantages of both classes of drugs together, and there is preclinical evidence suggesting the possibility of synergy between these agents (Kolesnikov et al, 2003b;Zelcer et al, 2005). Opiates also are used extensively with local anesthetics, particularly when administered epidurally or intradurally (Nordberg, 1984;Payne, 1987;Arner et al, 1988), an approach validated in animal models (Durant and Yaksh, 1986).…”