Which true opioid agonist lacks action at delta and kappa receptors?

Remifentanil is a true opioid agonist characterized by its selective action primarily at the mu receptor while showing negligible activity at the delta and kappa receptors. This selectivity is significant because it means that remifentanil's analgesic effects primarily derive from mu receptor activation, which is typically associated with pain relief and sedation.

In clinical practice, remifentanil is often used for its rapid onset and short duration of action, making it particularly suitable for procedures requiring quick recovery, such as outpatient surgeries. This pharmacological profile differentiates it from other opioid agonists that might interact at delta or kappa receptors, which can lead to different side effects or nonefficacy in certain contexts.

Understanding the receptor selectivity of opioid agonists is crucial for clinicians to tailor pain management strategies effectively, ensuring adequate analgesia while minimizing adverse effects associated with broader receptor interactions.