Irritation or damage to lumbar nerve roots referred to as lumbar radiculopathy or sciatica is a very common clinical entity with a lifetime prevalence of 1-3% in the adult population. Lumbar radiculopathy typically causes back pain and sharp, shooting pain in the leg(s). Despite its prevalence and disabling characteristics, sciatica has never been selectively studied in drug trials. It is plausible to assume that tricyclic antidepressants and opioids, which are effective in the treatment of other neuropathic pain syndromes will be beneficial for chronic lumbar radicular pain as well. This is a randomized, double-blind, placebo-controlled, four period cross-over study of chronic lumbar radicular pain. Patient selection will target men and women of all ethnic backgrounds between the ages of 18 and 65 who have had signs and symptoms of sciatica for 3 months or more. Treatments are: 1. nortriptyline (25-100 mg); 2. morphine (MS Contin 30-90 mg); 3. nortriptyline (25-100 mg) plus morphine, (MS Contin 30-90 mg); 4. combination of an active placebo, benztropine (0.25-1 mg) and an inert placebo. Patients will be called twice a week to individually titrate doses and monitor side effects. The primary outcome measures in this study will be the daily pain scores in the low back, in the leg and combined. Patients' quality of life and activities of daily living will be secondary outcome measures as assessed by the SF 36 and Oswestry and the Beck questionnaires. Fifty one patients will be enrolled in this study and the duration of the study will be 37 weeks.