Comprehensive Review on Alzheimer Disease: Causes, Risk Factors, Pathology, Mechanisms

Alzheimer’s disease (AD) is the most widespread neurodegenerative disorder and a leading cause of dementia seen in clinical practice. Although many therapeutic strategies have been explored, AD continues to present a major challenge for healthcare systems around the world. This article begins by summarizing the key biological processes that lead to neuronal damage in AD. It then critically examines important research on current pharmacological treatments and highlights recent innovations and developing therapies. The review covers the main characteristics, classification, FDA approval status, mechanisms of action, therapeutic benefits, and common adverse effects of both established and emerging drugs for AD management. Traditional drug classes discussed include cholinesterase inhibitors, monoclonal antibodies, and other therapies such as memantine, valproic acid, and rosiglitazone. The article also explores newer monoclonal antibodies—donanemab, gantenerumab, solanezumab, bapineuzumab, crenezumab, and semorinemab—and evaluates nutritional supplements like vitamin E (alpha-tocopherol) and caprylidene. Additional agents that target tau and amyloid pathways, such as methylthioninium (MT), leuco-methylthioninium bis (LMTM), and tramiprosate, are reviewed for their ability to inhibit Aβ aggregation. The discussion extends to antidiabetic and anti-inflammatory drugs recently proposed for AD therapy. These include NE3107, a compound with anti-inflammatory and insulin-sensitizing effects, and the commonly used antidiabetic drug metformin. Anti-neuroinflammatory agents— such as sodium oligomannate (GV-971), intravenous immunoglobulin infusions to reduce circulating Aβ components, and masitinib, a tyrosine kinase inhibitor affecting mast cells and microglia—are also highlighted.