Perioperative Pain Management to Prevent the Evolution of Acute Pain to Chronic Pain
AUSTIN, TX—Maximizing acute pain relief while minimizing the incidence of adverse events prevents the evolution of acute postoperative pain into chronic pain. At the American Pain Society's 30th Annual Scientific Meeting, Bruce Nicholson, MD, from the Pennsylvania State University School of Medicine, University Park, PA, presented evidence supporting four potential integrative pain management strategies: combining drugs of multiple therapeutic classes; optimizing the route of analgesia administration; use of single agents with two mechanisms of action; and fixed-dose combinations of opioids.
- A reduction in the incidence of postoperative neuropathic pain was observed when 300mg of pregabalin, an anticonvulsant with analgesic properties, was administered prior to and for 14 days following total knee arthroplasty in combination with opioid therapy. Data presented by Dr. Nicholson showed the incidence of postoperative neuropathic pain to be 0% with pregabalin compared with 8.7% and 5.2% for placebo at three months and six months, respectively. Additionally, he stated, there was a reduction in the use of epidural opioids (P=0.003).
- Optimizing the route (IV vs. epidural) of intraoperative and postoperative analgesia may be another approach to reduce residual pain. Additionally, because opioids may produce hyperalgesia, combination therapy with a hyperalgesic agent (eg, ketamine) may be more efficacious in providing pain relief. In a randomized controlled trial, intraoperative and postoperative IV lidocaine-sufentanil-clonidine was compared with epidural bupivacaine-sufentanil-clonidine in combination with intraoperative ketamine. Study results showed that patients who received epidural bupivacaine-sufentanil-clonidine in combination with ketamine experienced reduced postoperative residual pain compared with IV analgesia plus ketamine.
- Agents that exert their analgesic effects via two mechanisms of action may also be an effective option for preventing chronic postoperative pain, such as tapentadol, a mu-opioid agonist and norepinephrine reuptake inhibitor, states Dr. Nicholson. Studies show that tapentadol produced a greater mean sum pain intensity difference at 24 hours (SPID24) of 73.3 compared with 5.2 for placebo (P<0.001). Additionally, tapentadol has an improved adverse event profile, particularly for gastrointestinal effects, compared with a traditional opioid such as oxycodone.
- An investigational combination opioid drug, Q8003 (morphine 6mg/oxycodone 4mg) is currently in development. Clinical data presented showed that Q8003 produced comparable analgesia compared with morphine 12mg or oxycodone 8mg monotherapy; SPID24 30 vs 28.5 and 35.7, respectively. Dr. Nicholson highlighted that combination therapy improved tolerability. Rates of gastrointestinal effects (ie, nausea and vomiting) were considerably reduced with Q8003 compared the individual agents. The importance of drugs that offer improved tolerability, he states, is that “patients want to avoid these GI side effects of their pain medications and may prefer pain. This trade-off results in patients experiencing persistent pain that may develop into long-term chronic pain.”