Underlying Factors that Exist Outside of Pain Drive Prescription Opioid Use Postsurgery
LAS VEGAS—Preoperative symptoms of self-loathing are just one of many factors that can predict prolonged opioid use after surgery, and supports a “self-medication hypothesis” in which patients with affective-cognitive distress find their mood enhanced with opioids, leading to reinforcement.
In fact, patients exhibit wide variability in opioid needs after similar surgical procedures, said Jennifer Hah MD, MS, instructor in the Department of Anesthesiology, Perioperative, and Pain Medicine, at Stanford University, Stanford, California, who explored what is known about risk factors for persistent opioid use in her presentation.
“The amount of prescribed opioids does not influence whether patients decide to continue or discontinue their opioid use,” she said. “There are some underlying factors that exist outside of pain that are driving a patient's decision.”
Compared with those who use nonsteroidal antiinflammatory agents to treat chronic pain, increased rates of substance abuse and depression are observed in long-term prescription opioid users. However, pain intensity does not predict treatment with opioids versus nonopioid analgesics. Depression and anxiety also can contribute to substance use disorders among long-term opioid users. A total of 45 million Americans undergo surgery every year, “and the majority of these patients are going to have sort of controlled injury through their surgery and they are going to have pain and they are most likely going to require some sort of prescription opioid medication,” Dr. Hah said.
This creates an ideal model to study how patients respond to injury, resulting pain, and prescription opioid exposure. Chronic postsurgical pain affects 10% of patients, and certain operations have a higher rate of postsurgical pain.
In a study that examined opioid consumption following outpatient upper extremity surgery, 250 patients were contacted 7-14 days after surgery. Invariably, the patients received 30 opioid pills; medication use varied from 9-14 pills. Of the patients, 4% refilled their opioid prescription and 3% intended to refill their prescription.
Low-pain surgeries that exposed elderly adults to new prescription opioids increased the risk of long-term opioid use by 44% one year after surgery, Dr. Hah said, adding that even opioids prescribed for outpatient or short-stay surgeries increase the risk of persistent opioid use. One study found that more than 60% of people receiving 90 days of continuous opioid therapy remained on opioids years later.
Dr. Hah explained there is a critical time frame before and immediately after nerve injury exists in which specific interventions can reduce the incidence and intensity of chronic neuropathic pain behaviors.
Gabapentin and pregabalin have been shown to reduce opioid consumption and postoperative pain scores by 50%. One study showed that when administered preoperatively, a significant decrease in morphine consumption at 24 hours was observed. Patients also had a significant decrease in visual analog scale scores at 24 hours and a significantly decreased risk of nausea.
Perioperative ketamine, which has opioid-sparing effects, provides immediate postoperative analgesia and improved pain control in chronic opioid users; however, the effect on chronic postsurgical pain is unclear. Ketamine should be used with caution in patients with liver disease, Dr. Hah said.
A study of the analgesic efficiency of combined pregabalin and ketamine for total hip arthroplasty found that 48-hour morphine use was reduced; however, no difference in pain scores or adverse effects were found.
Additional techniques that can be used to reduce persistent postoperative opioid use and chronic postsurgical pain include regional and epidural anesthesia, wound infiltration with local anesthetic, and EMLA cream, applied postsurgically and daily for 4 days. Of myriad reasons to decrease prescription opioid use after surgery, paramount is that prescription opioids are the leading cause of overdose deaths in the US, often in the context of polypharmacy. Overdose death rates, prescription opioid sales, and substance abuse treatment admissions have all climbed in parallel over the past decade, Dr. Hah said, and the cost of nonmedical prescription opioid use is now more than $50 billion annually.
Negative attributes of prescription opioids include tolerance/physical dependence, immunosuppression, opioid-induced endocrinopathy, and opioid-induced hyperalgesia.
She said that positive toxicology results at the time of injury predicts an extended duration of postoperative prescription opioid use. One study found that compared with opioid-naive women, 30% of women taking preoperative opioids were taking them 6 months after gynecologic surgery.