Maintenance of Effect of Duloxetine in Patients With Diabetic Peripheral Neuropathic Pain (DPNP)

• Maintenance Arm: Number of Patients With a ≥50% Reduction From Baseline (Week 0) in Brief Pain Inventory 24-hour Average Pain Item [ Time Frame: Baseline (Week 0), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the severity of pain based on the average pain over the past 24-hours. The severity scores range from 0 (no pain) to 10 (pain as severe as you can imagine).
• Rescue Arm: Number of Patients With a ≥50% Reduction From Baseline (Week 0) in Brief Pain Inventory 24-hour Average Pain Item [ Time Frame: Baseline (Week 0), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the severity of pain based on the average pain over the past 24-hours. The severity scores range from 0 (no pain) to 10 (pain as severe as you can imagine).
• Maintenance Arm: Change From Baseline (Week 8) in Brief Pain Inventory Worst Pain Score at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the severity of pain based on the worst pain experienced over the past 24-hours. The severity scores range from 0 (no pain) to 10 (pain as severe as you can imagine).
• Rescue Arm: Change From Baseline (Week 8) in Brief Pain Inventory Worst Pain Score at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the severity of pain based on the worst pain experienced over the past 24-hours. The severity scores range from 0 (no pain) to 10 (pain as severe as you can imagine).
• Maintenance Arm: Change From Baseline (Week 8) in Brief Pain Inventory Least Pain Score at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the severity of pain based on the least pain experienced over the past 24-hours. The severity scores range from 0 (no pain) to 10 (pain as severe as you can imagine).
• Rescue Arm: Change From Baseline (Week 8) in Brief Pain Inventory Least Pain Score at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the severity of pain based on the least pain experienced over the past 24-hours. The severity scores range from 0 (no pain) to 10 (pain as severe as you can imagine).
• Maintenance Arm: Change From Baseline (Week 8) in Brief Pain Inventory Average Pain Score at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the severity of pain based on the average pain experienced over the past 24-hours. The severity scores range from 0 (no pain) to 10 (pain as severe as you can imagine).
• Rescue Arm: Change From Baseline (Week 8) in Brief Pain Inventory Average Pain Score at 34 Week Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the severity of pain based on the average pain experienced over the past 24-hours. The severity scores range from 0 (no pain) to 10 (pain as severe as you can imagine).
• Maintenance Arm: Change From Baseline (Week 8) in Brief Pain Inventory Pain Right Now Score at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the severity of pain based on the pain right now. The severity scores range from 0 (no pain) to 10 (pain as severe as you can imagine).
• Rescue Arm: Change From Baseline (Week 8) in Brief Pain Inventory Pain Right Now Score at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the severity of pain based on the pain right now. The severity scores range from 0 (no pain) to 10 (pain as severe as you can imagine).
• Maintenance Arm: Change From Baseline (Week 8) in Brief Pain Inventory Interference Score: General Activity at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the interference of pain in the past 24 hours on general activity. The Interference scores range from 0 (does not interfere) to 10 (completely interferes).
• Rescue Arm: Change From Baseline (Week 8) in Brief Pain Inventory Interference Score: General Activity at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the interference of pain in the past 24 hours on general activity. The Interference scores range from 0 (does not interfere) to 10 (completely interferes).
• Maintenance Arm: Change From Baseline (Week 8) in Brief Pain Inventory Interference Score: Mood at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the interference of pain in the past 24 hours on mood. The Interference scores range from 0 (does not interfere) to 10 (completely interferes).
• Rescue Arm: Change From Baseline (Week 8) in Brief Pain Inventory Interference Score: Mood at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the interference of pain in the past 24 hours on mood. The Interference scores range from 0 (does not interfere) to 10 (completely interferes).
• Maintenance Arm: Change From Baseline (Week 8) in Brief Pain Inventory Interference Score: Walking Ability at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the interference of pain in the past 24 hours on walking ability. The Interference scores range from 0 (does not interfere) to 10 (completely interferes).
• Rescue Arm: Change From Baseline (Week 8) in Brief Pain Inventory Interference Score: Walking Ability at 34 Week Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the interference of pain in the past 24 hours on walking ability. The Interference scores range from 0 (does not interfere) to 10 (completely interferes).
• Maintenance Arm: Change From Baseline (Week 8) in Brief Pain Inventory Interference Score: Normal Work at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the interference of pain in the past 24 hours on normal work. The Interference scores range from 0 (does not interfere) to 10 (completely interferes).
• Rescue Arm: Change From Baseline (Week 8) in Brief Pain Inventory Interference Score: Normal Work at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the interference of pain in the past 24 hours on normal work. The Interference scores range from 0 (does not interfere) to 10 (completely interferes).
• Maintenance Arm: Change From Baseline (Week 8) in Brief Pain Inventory Interference Score: Relations With Other People at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the interference of pain in the past 24 hours on relations with other people. The Interference scores range from 0 (does not interfere) to 10 (completely interferes).
• Rescue Arm: Change From Baseline (Week 8) in Brief Pain Inventory Interference Score: Relations With Other People at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the interference of pain in the past 24 hours on relations with other people. The Interference scores range from 0 (does not interfere) to 10 (completely interferes).
• Maintenance Arm: Change From Baseline (Week 8) in Brief Pain Inventory Interference Score: Sleep at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the interference of pain in the past 24 hours on sleep. The Interference scores range from 0 (does not interfere) to 10 (completely interferes).
• Rescue Arm: Change From Baseline (Week 8) in Brief Pain Inventory Interference Score: Sleep at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the interference of pain in the past 24 hours on sleep. The Interference scores range from 0 (does not interfere) to 10 (completely interferes).
• Maintenance Arm: Change From Baseline (Week 8) in Brief Pain Inventory Interference Score: Enjoyment of Life at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the interference of pain in the past 24 hours on enjoyment of life. The Interference scores range from 0 (does not interfere) to 10 (completely interferes).
• Rescue Arm: Change From Baseline (Week 8) in Brief Pain Inventory Interference Score: Enjoyment of Life at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures the interference of pain in the past 24 hours on enjoyment of life. The Interference scores range from 0 (does not interfere) to 10 (completely interferes).
• Maintenance Arm: Change From Baseline (Week 8) in Brief Pain Inventory Average Interference at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures interference of pain on average of the 7 questions assessing the interference of pain for general activity, mood, walking ability, normal work, relations with other people, sleep, and enjoyment of life. The average Interference scores range from 0 (does not interfere) to 10 (completely interferes).
• Rescue Arm: Change From Baseline (Week 8) in Brief Pain Inventory Average Interference at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A self-reported scale that measures interference of pain on average of the 7 questions assessing the interference of pain for general activity, mood, walking ability, normal work, relations with other people, sleep, and enjoyment of life. The average Interference scores range from 0 (does not interfere) to 10 (completely interferes).
• Maintenance Arm: Patient's Global Impressions of Improvement (PGI-I) at Week 34 Endpoint [ Time Frame: Week 34 ] [ Designated as safety issue: No ]
  A scale that measures the patient's perception of improvement at the time of assessment compared with the start of treatment. The score ranges from 1 (very much better) to 7 (very much worse).
• Rescue Arm: Patient's Global Impressions of Improvement (PGI-I) at Week 34 Endpoint [ Time Frame: Week 34 ] [ Designated as safety issue: No ]
  A scale that measures the patient's perception of improvement at the time of assessment compared with the start of treatment. The score ranges from 1 (very much better) to 7 (very much worse).
• Maintenance Arm: Change From Baseline (Week 8) in Clinical Global Impressions of Severity (CGI-S) at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  Measures severity of illness at the time of assessment compared with start of treatment. Scores range from 1 (normal, not at all ill) to 7 (among the most extremely ill patients).
• Rescue Arm: Change From Baseline (Week 8) in Clinical Global Impressions of Severity (CGI-S) at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  Measures severity of illness at the time of assessment compared with start of treatment. Scores range from 1 (normal, not at all ill) to 7 (among the most extremely ill patients).
• Maintenance Arm: Change From Baseline (Week 8) in Sensory Portion of the Short-Form McGill Pain Questionnaire at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  This instrument consists of 11 pain descriptors. The sensory pain portion scores range from 0 (none) to 3 (severe).
• Rescue Arm: Change From Baseline (Week 8) in Sensory Portion of the Short-Form McGill Pain Questionnaire at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  This instrument consists of 11 pain descriptors. The sensory pain portion scores range from 0 (none) to 3 (severe).
• Maintenance Arm: Change From Baseline (Week 8) in Beck Depression Inventory-II (BDI-II) Total Score at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A 21-item, patient-completed questionnaire to assess characteristics of depression. Each of the 21 items corresponding to a symptom of depression is summed to give a single score. There is a four-point scale for each item ranging from 0 to 3. Total score of 0-13 is considered minimal range, 14-19 is mild, 20-28 is moderate, and 29-63 is severe.
• Rescue Arm: Change From Baseline (Week 8) in Beck Depression Inventory-II (BDI-II) Total Score at Week 34 Endpoint [ Time Frame: Baseline (Week 8), Week 34 ] [ Designated as safety issue: No ]
  A 21-item, patient-completed questionnaire to assess characteristics of depression. Each of the 21 items corresponding to a symptom of depression is summed to give a single score. There is a four-point scale for each item ranging from 0 to 3. Total score of 0-13 is considered minimal range, 14-19 is mild, 20-28 is moderate, and 29-63 is severe.
• Number of Participants Discontinuing in the Acute Phase [ Time Frame: Baseline (Week 0) to Week 8 ] [ Designated as safety issue: Yes ]
• Number of Participants Discontinuing in Maintenance / Rescue Phase [ Time Frame: Baseline (Week 8) to Week 34 ] [ Designated as safety issue: Yes ]
• Change From Baseline in Vital Signs: Heart Rate at Week 34 Endpoint [ Time Frame: Baseline (Week 0), Week 34 ] [ Designated as safety issue: Yes ]
• Change From Baseline (Week 0) in Vital Signs: Diastolic Blood Pressure at Week 34 Endpoint [ Time Frame: Baseline (Week 0), Week 34 ] [ Designated as safety issue: Yes ]
• Change From Baseline (Week 0) in Vital Signs: Systolic Blood Pressure at Week 34 Endpoint [ Time Frame: Baseline (Week 0), Week 34 ] [ Designated as safety issue: Yes ]
• Change From Baseline (Week 0) in Vital Signs: Weight at Week 34 Endpoint [ Time Frame: Baseline (Week 0), Week 34 ] [ Designated as safety issue: Yes ]

• Efficacy of duloxetine 60 mg over 8 weeks and 6 months and duloxetine 120 mg over 6 months, using Short-Form McGill, Patient's Global Impressions of Improvement, Clinical Global Impressions of Severity, and Brief Pain Inventory
• Efficacy of duloxetine 120 mg over 6 month period in patients with diabetic peripheral neuropathic pain who fail to achieve 30% pain reduction after being on 60 mg for 8 weeks using the Brief Pain Inventory
• Evaluate the safety of duloxetine 60 mg during 8 weeks of acute therapy and 6 months of rescue therapy along with 120 mg during 6 months of rescue therapy

To determine if duloxetine 60 mg once daily can work up to 6 months in treating pain from Diabetic Neuropathy.

• Skljarevski V, Desaiah D, Zhang Q, Chappell AS, Detke MJ, Gross JL, Ziegler D. Evaluating the maintenance of effect of duloxetine in patients with diabetic peripheral neuropathic pain. Diabetes Metab Res Rev. 2009 Oct;25(7):623-31.
• Hall JA, Wang F, Oakes TM, Utterback BG, Crucitti A, Acharya N. Safety and tolerability of duloxetine in the acute management of diabetic peripheral neuropathic pain: analysis of pooled data from three placebo-controlled clinical trials. Expert Opin Drug Saf. 2010 Jul;9(4):525-37.

Inclusion Criteria:

• Have pain due to bilateral peripheral neuropathy caused by Type I or Type II diabetes with the pain beginning in the feet and present for at least 6 months.
• May not be pregnant and agree to utilize medically acceptable and reliable means of birth control during participation in the study.
• Score of 4 or greater on the Brief Pain Inventory on the 24-hour average pain item.

Exclusion Criteria:

• History of substance abuse or dependence within the past year, excluding nicotine and caffeine.
• Serious or unstable cardiovascular, hepatic (acute liver injury such as hepatitis or severe cirrhosis),kidney, respiratory, or blood disorder, seizure disorder, problems with peripheral vascular disease, or other medical conditions or psychiatric conditions that would hinder your participation or be likely to lead to hospitalization during the course of the study.
• Taking monoamine oxidase inhibitor (MAOI) within 14 days of starting the study or the potential need to take during or within 5 days after discontinuation from the study.
• Treatment with fluoxetine within 30 days of starting the study.
• Unstable blood sugar control and uncontrolled or poorly controlled hypertension.