Thiafentanil (A-3080, Thianil) is a highly potent opioid analgesic that is an analog of fentanyl, and was invented in 1986. It is similar to carfentanil though with a faster onset of effects, shorter duration of action and a slightly lesser tendency to produce respiratory depression. It is used in veterinary medicine to anesthetise large animals such as impala, usually in combination with other anesthetics such as ketamine, xylazine or medetomidine to reduce the prevalence of side effects such as muscle rigidity.