“Post Operative Pain Management in the Chronic Pain or Opioid Dependent Patient”
What is Pain?
-an unpleasant sensory and emotional experience
-associated with actual or potential tissue damage
Why is it important to control post operative pain?
- Patient satisfaction; humane treatment
- Myocardial infarction or ischemia; tachycardia and dysrhythmia
- Atelectasis; thromboembolic events;
- Wound healing; peripheral vasoconstriction; and metabolic acidosis
Why is post operative pain more difficult to manage in opioid dependent patients?
- sensitization of the CNS to pain
- tolerance, receptor down regulation
- fear and anxiety
- withdrawal (hypertension, tachycardia, lacrimation, rhinorrhea, papillary dilation, piloerection,
sweating, diarrhea, fever, insomnia, nausea, vomiting, aches, yawning, dysphoria)
How much opioid should we give?
- no magic number but may need to be increased by 30 to 100% in comparison to
requirements in opioid naïve patients
- because of stigma, many patients underreport home narcotic requirements
- preoperative administration of daily maintenance or baseline opioid dose or equivalent dose
may be given intraoperatively if missed
What are some adjuvant therapies we might try to further control pain?
- Centrally acting Alpha-2 Agonists
Clonidine (opioid sparing, treats sympathetic response to withdrawal, sedating,
hypotension)
Dexmedetomidine (easy arousability, analgesia, no respiratory depression, limited or
no hypotension)
- Muscle Relaxants - mild to moderate sedation, skeletal muscle spasm and cramping
Robaxin
Tizanidine (alpha 2 agonist)
Baclofen (GABA analog, trigeminal neuralgia)
- Benzodiazepines - anxiolitic, sedating, muscle relaxant
- NMDA Antagonists (receptor involved in modulating chronic pain and opioid mechanisms)
Ketamine (dissociative anesthetic, profound analgesia, may help modify opioid
tolerance and withdrawal, 0.05mg/kg)
Dextrmethorphan (antitussive), Amantadine (antiviral), Memantine (Alzheimer’s)
- Membrane stabilizers - neuropathic pain
Gabapentin (preop?)
Magnesium Sulfate IV
- NSAIDs: Ketorolac (caution in pt with impaired renal, GI, platelets)
- Tylenol: PR? IV formulation on the horizon
- Coriticosteroids: Decadron (can also improve nausea, malaise)
- Local, regional, and neuraxial anesthesia