Opioid Agonist-Antagonists

What is the prototype?

Pentazocine

• ATI: butorphanol

• Given PO, SC, IM, and IV

Why is it prescribed?

Relief of moderate-severe pain, adjunct to general anesthesia, pain relief in L&D, and can also be used in the treatment of opioid dependence/addiction

How does it work?

Acts at some opioid receptors to produce analgesia, sedation, and euphoria, while also blocking some opioid receptors (i.e., preventing analgesia, sedation, and euphoria)

What happens if there is too much drug effect?

Same as opiates

• Respiratory depression, orthostatic hypotension, constipation, CNS depressant (i.e., falls), GU effects (i.e., urinary retention), and dependence

What is important to remember about this medication (3)?

• Will likely cause opiate withdrawal effects if given as a replacement for a high dose or long-term opiate agonist therapy because of the antagonistic effects

• Still can cause respiratory depression, hypotension, etc.

• Monitor kidney function, balance, confusion, I/O, GI function (i.e., constipation), sedation, SpO2, respirations, and BP

What do you need to tell a patient taking this medication (5)?

Same as with opiate agonists

• Take the lowest dose for the shortest time-period needed for pain management

• Fall precautions and avoid dangerous activities like driving etc.

• Increase fluids and fiber to prevent/treat constipation

• Watch for signs of dependency

• Watch for signs of depression