Chronic pain in patients with Alzheimer's disease or dementia is a complex issue in the medical field; these patients suffer from the common causes of chronic pain, especially in geriatric medicine. To ensure the correct type and level of given treatment, medical care should be taken to avoid the contribution of chronic pain and cognitive impairment in the elderly population. Acetylcholinesterase inhibitors (AChE-Is) have been proven as an efficient therapeutic resource for significant improvement in dementia of Alzheimer's disease and chronic pain due to the fact that cholinergic deficit is considered as an early finding in cognitive impairment and persisting pain. Some AChE-Is are investigated here in terms of treatment of dementia and chronic pain management. Neostigmine has been used as an adjunct analgesic in the postoperative period and in combination with other analgesic medications in an intrathecal approach. Rivastigmine has, over the past ten years, become the approved agent for the management of dementia of mild to moderate Alzheimer's disease and has gained approval for treating different types of non-Alzheimer's dementia. In this review, we will focus on the two types of AChE-Is (rivastigmine and neostigmine) in the development of their clinical use and their respective mechanisms of actions on improving cognitive function and managing chronic pain.

Complex regional pain syndrome (CRPS) is a condition of neuropathic pain, which is characterized by significant autonomic and inflammatory features. CRPS occurs in patients who have limb surgery, limb fractures, or trauma. Many patients may have pain resolve within twelve months of the inciting incident; however, a small subset progresses to the chronic form. This transitional process often happens by changing from warm CRPS with dominant inflammatory phase to cold CRPS, in which autonomic characteristics or manifestations dominate. Several peripheral and central mechanisms are involved, which might vary among individuals over a period of time. Other contributors include peripheral and central sensitization, autonomic alterations, inflammatory and immune changes, neurochemical changes, and psychological and genetic factors. Although effective management of the chronic CRPS form is often challenging, there are a few high quality randomized controlled trials that support the efficacy of the most commonly used therapeutic approaches.

No abstract