Date: {{$ActivityAssignDate}}

Dear Dr. {{$doctorName}} ,


Subject: A retrospective cross-sectional, observational survey study to analyze role of Duloxetine in diabetic peripheral neuropathic pain in adults.


Pain is an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage. As such, pain is a warning about tissue damage signalled by specific receptors and fiber systems extending from the periphery to the brain. Pain can be experienced as an acute, chronic or intermittent sensation, or as a combination of the three, and is reported to be the common reason for medical visits. Acute pain, the most commonly experienced type of pain, may be a result of injuries, acute illnesses, surgeries or labor.1


The International Association for the Study of Pain (IASP) defines neuropathic pain as pain caused by a lesion or disease of the somatosensory nervous system.2 This definition replaces an older definition according to which neuropathic pain was “pain initiated or caused by a primary lesion, dysfunction, or transitory perturbation of the peripheral or central nervous system”.3


Two changes are important in this change of definition: dysfunction and the neuronal lesion.

  1. In the new definition of neuropathic pain, dysfunction is no longer accepted as a criterion because it is difficult to accept symptoms and soft signs as criteria if they cannot be verified objectively.

  2. It is now specified that the lesion needs to affect the somatosensory system meaning that lesions or diseases outside the somatosensory pathways, e.g., the cerebellum, does not qualify as neuropathic.

Neuropathic pain is a chronic condition which represents a significant burden for patients, society and healthcare systems.4 The prevalence of neuropathic pain in the general population has been estimated at 6.9–10.0%.​5

Management includes effective pharmacotherapy options for patients with painful diabetic neuropathy like serotonin-norepinephrine reuptake inhibitors (duloxetine, venlafaxine), tricyclic antidepressants (amitriptyline, desipramine, nortriptyline), and gabapentinoid antiseizure medications (pregabalin, gabapentin). All have been shown to be more effective than placebo in randomized trials, and limited comparative data suggest that efficacy is similar across agents.

The four main reasons that treatments for diabetic neuropathic pain fail are:

  1. Inadequate diagnosis and a lack of appreciation of the mechanisms involved

  2. Insufficient management of psychological comorbid conditions

  3. Incorrect understanding or selection of treatment options

  4. Use of inappropriate outcomes measures


Duloxetine

Duloxetine is a selective serotonin and norepinephrine reuptake inhibitor that is approved by the FDA for major depressive disorder, generalized anxiety disorder, diabetic peripheral neuropathic pain, and fibromyalgia. Its mechanism of action is through the blockade of reuptake of serotonin (5-HT) and norepinephrine. Studies show that duloxetine inhibits 5-HT and norepinephrine uptake in the hypothalamic synaptosomes of rats with a preference for 5-HT.6

Metanalysis assessing the benefits and harms of duloxetine for treating painful neuropathy and different types of chronic pain shows that there was moderate quality evidence that duloxetine reduced pain in both painful diabetic peripheral neuropathy and fibromyalgia. In diabetic peripheral neuropathic pain, a 50% or better improvement with duloxetine 60 mg per day was just over one and a half times more likely than with placebo.​7

Duzela (Duloxetine 20/30/40/60 mg) capsules are marketed by Sun Pharmaceutical Industries Ltd. Although every product is marketed only after regulatory approval, it is important to know how it performs in day-to-day practice of individual medical practitioners. For this purpose, we have planned to conduct a survey to analyze efficacy & safety of Duloxetine in diabetic peripheral neuropathic pain in adults.

We invite you to participate in this data collection activity. All you need to do is to report on a standard form your experience with this combination drug in the normal course of your practice. If you agree to participate, you will need to fill data collection forms (which we call DCF).

We trust you and we are partners in promoting this well tolerated and effective drug therapy. In that spirit we hope you will consent to participate in this study. If you do, please sign and return the enclosed reply along with your visiting card for accuracy of records.



Yours truly,


Sun Pharma Laboratories Limited,