Opioid Agonists

What is the prototype?

Morphine

• Given PO, IV, epidural, intrathecal, and suppository

• “Wet blanket, everything goes down”

Why is it prescribed?

Treats moderate to severe pain, used for sedation (i.e., pre-op med and adjunct to anesthesia), treatment during acute MI, and is a cough suppressant

How does it work?

Acts at specific opioid receptors in CNS, producing analgesia, sedation, euphoria, and antitussive effects (i.e., cough suppressant)

What happens if there is too much drug effect?

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 (5)?

• Caution

  • In the presence of respiratory dysfunction and hypotension/possible hypotension

  • After recent GI/GU surgery due to risk of constipation and urinary retention

  • In pregnancy and lactation (i.e., risk vs reward)

• Naloxone is the treatment for overdose

• Contraindicated in diarrhea, r/t to toxic poisons, post-biliary surgery, and anastomosis procedures (i.e., GI surgery)

• Watch for additive effects of any drug that has similar effects like MAOIs, barbiturates, anesthesia, phenothiazines (i.e., antipsychotics), anti-seizure drugs, muscle relaxers, and antihistamines

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

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

• 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