Conditions: Diabetic Neuropathy, Painful
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 407
Healthy volunteers: no

Brief summary:
To test the non-inferiority of duloxetine monotherapy as a treatment for the management of diabetic peripheral neuropathic pain as compared to pregabalin treatment among patients who have not had an adequate response to gabapentin.

Detailed description:

Arms:
arm 1: Pregabalin (PGB) 50 milligram (mg) three times a day (TID) (US \& Germany) or 75 mg twice daily (BID) (Canada), orally (PO) for 2 weeks, then PGB 100 mg TID (US \& Germany) or 150 mg BID (Canada), PO for 10 weeks. arm 2: Duloxetine (DLX) 30 milligram (mg) once daily (QD), orally (PO) for 1 week, then DLX 60 mg QD, PO for 11 weeks. arm 3: Stable Gabapentin (GAB) + Duloxetine (DLX) 30 milligram (mg) once daily (QD), orally (PO) for 1 week, then stable GAB + DLX 60 mg QD, PO for 11 weeks.

Interventions: intervention 1: duloxetine hydrochloride intervention 2: pregabalin intervention 3: gabapentin
Intervention descriptions: intervention 1: Duloxetine (DLX) once daily (QD), orally (PO) intervention 2: Pregabalin (PGB) orally (PO) intervention 3: Stable Gabapentin (GAB) (participants will remain on the same dose of gabapentin at which they entered the study)

Protocol document: