Tramadol is a centrally-acting synthetic opioid analgesic. Its primary pharmacological effect is to bind to the µ-opioid receptor and inhibit the reuptake of serotonin, norepinephrine, and dopamine in the central nervous system (CNS). It was patented in 1977, but was not marketed until 1995 due to extensive testing for safety concerns.

The U.S. Food and Drug Administration (FDA) approved Tramadol in 1995 under the trade name Ultram after concluding that it had lower abuse rates than traditional opioids like Percocet or Vicodin – which are often prescribed following surgeries or accidents when patients might be more susceptible to addiction.

Tramadol is available in many countries, including Canada under the brand name Tramal, Roxicodone in the United States, and Tramil in Mexico and various other countries. In some places it is restricted to prescription only, while in others it can be obtained over-the-counter. It also comes in injection form.

Tramadol was developed by the German pharmaceutical company Grünenthal GmbH (now Grünenthal plc) and was patented by Karl Köllisch. It first went on sale in Germany under the brand name Tramal on 17 August 1995. Grünenthal had sold tramadol generically since 1988 before its patent expired in 1996.