Kidney disease is a public health problem because of: Its ever-increasing incidence The high associated mortality and the cost of its management. It affects 10% of adults worldwide in its chronic form. Hypertension, diabetes, chronic infections are the main risk factors but also nephrotoxic substances. Which represents 5% of the causes. Among these nephrotoxic substances: analgesics occupy a proportion of 20%, but also Opiates (heroin and cocaine). However, in sub-Saharan Africa, and in Cameroon in particular, tramadol, a second-tier analgesic derived from opioids, used clinically for the treatment of pain, has been increasingly found in illicit channels and abused since 2003. In addition, the increase in the number of patients with end-stage renal disease, which rose from 30 in 2000 to 497 in 2012 in Cameroon, has led to the question of whether chronic users of tramadol are at risk of developing renal disease.