“Butorphanol More Effective than Tramadol in Treating Shivering after Spinal Anesthesia: A Comparative Study on Onset Time and Cessation Rate”

https://pubmed.ncbi.nlm.nih.gov/38116041

In the treatment of shivering after spinal anesthesia, butorphanol has a shorter onset time and higher cessation rate within 1 minute compared to tramadol, making it a more effective treatment option.