Pharmacological Diversity in Opioid Analgesics: Lessons From Clinically Useful Drugs

Opioid analgesics have been used for centuries for the treatment of acute and chronic pain conditions. In the acute surgical or injury pain setting, their efficacy is a mainstay; however, for the management of chronic pain, their use may be limited due to a myriad of unwanted side effects. Attempts have been made to reduce these side effects by modifying opioid drugs to impart diverse pharmacological properties ranging from varying efficacy and selectivity to diversifying downstream receptor signaling. In this review we discuss how recently developed compounds compare to conventional agonists such as morphine and fentanyl and discuss strategies that could contribute to improve opioid utility while limiting side adverse events.