Opiates affect receptors located in the spinal cord and brain. These receptors are also present at the site of injury. When opiates are present in the brain, euphoria and sedation can be produced. These drugs alter the mind's perception of painful stimuli. At the level of the spinal cord, opiates deaden painful impulses transmitted from the peripheral nerves.
Local anesthetics block nerve impulses.
Depending on the type and concentration of anesthetic, painful impulses can be stopped while a patient is still conscious and able to move. Unrelieved or poorly controlled postoperative pain is associated with an increase in postoperative illness in children and adults. In contrast, critically ill patients requiring intensive-care unit admission may have their stays shortened with aggressive pain management. Children who require frequent hospitalizations experience marked anxiety and fear about painful medical procedures. The Nemours Foundation is a nonprofit organization devoted to children's health and is the largest physician practice delivering subspecialty pediatric care in the United States.