A randomized double blind Trial comparing Efficacy and Safety of Duloxetine vs. Amitriptyline in painful Diabetic Neuropathy

Painful peripheral diabetic neuropathy is a chronic complication of diabetes characterized by intractable pain, which mainly affects the foot. The currently available treatments have their own limitations. A randomized, double blind, active control, cross over clinical trial with optional dose up-titration to compare the efficacy and safety of duloxetine with amitriptyline in controlling peripheral neuropathic pain was conducted. Though 76 patients were included, 65 were randomized and only 58 reported after taking at least one dose of the treatment. The pain relief was observed in 80% and 79% patients on amitriptyline and duloxetine respectively by Visual analogue scale. Patient global assessment, McGill pain questionnaire and Likert pain scale showed significant improvement with both treatments from second week itself. Amitriptyline and duloxetine showed more than 50% relief in pain in 56% and 58% respectively. However, not much improvement in other symptoms like numbness and paraesthesia could be achieved. Adverse events were more observed for amitriptyline. Most patients preferred amitriptyline dose 25mg once daily and duloxetine was preferred as 60 mg once daily at bedtime. Although both drugs showed comparable efficacy, of the two therapies duloxetine was preferred over amitriptyline due to its better tolerable adverse effect profile. There were self reported events of constipation and uneasiness noticed with duloxetine compared to dry mouth, sedation, dizziness and uneasiness while on amitriptyline. Comparing the efficacy and safety of the two drugs, duloxetine emerges as a better alternative due to comparable efficacy and a more tolerable adverse event profile. However, the cost may be the limiting factor and needs to be considered, especially in patients tolerable to amitriptyline.