2004b) Pain: moving from symptom control toward mechanism-specific pharmacologic management

Pain is a multidimensional sensory experience that isintrinsically unpleasant and associated with hurting and soreness. It may vary in intensity (mild, moderate, or severe), quality (sharp, burning, or dull), duration (tran-sient, intermittent, or persistent), and referral (superficial or deep, localized or diffuse). Although it is essentially a sensation, pain has strong cognitive and emotional compo-nents; it is linked to, or described in terms of, suffering. It is also associated with avoidance motor reflexes and alter-ations in autonomic output. All of these traits are inextri-cably linked in the experience of pain. Although we tend to think of pain as a homogeneous sensory entity, several distinct types exist: nociceptive, in-flammatory, neuropathic, and functional (Figure 1). The neurobiological mechanisms responsible for these different pains are beginning to be defined (1–3), providing insigh