This study will test the effectiveness of two drugs-nortriptyline and MS Contin (a type of morphine)-to treat pain caused by lumbar radiculopathy, or sciatica. Sciatica results from damage to the lumbar nerve roots, typically causing back pain and sharp, shooting pain down one or both legs. Although sciatica is common, there are no good treatments for it. Tricyclic antidepressants, such as nortriptyline, and opioids, such as morphine, have been effective in treating other kinds of pain from nerve damage.