S.F. is a 58-year-old woman with a long history of bilateral knee osteoarthritis. For the past several years, conservative treatment has included physical therapy and medications (oral cyclooxygenase-2 [COX-2] inhibitors and intra-articular triamcinolone acetonide injections). Because she has had progressively more pain and dysfunction over the past year, S.F. and her primary physician determined that it was time for bilateral total knee arthroplasties (TKA). The patient subsequently underwent bilateral TKA without complication. Postsurgical inpatient pain management includes oral oxycodone and a PCA pump with morphine sulfate for breakthrough pain. Early physical therapy interventions on postoperative days 1 and 2 focused on active and passive range of motion (ROM) of both lower extremities, transfer training, and upright mobility training. Prior to surgery, S.F. stated that her goal was to discharge from the hospital directly to her home. Her strong preference is not to be admitted to a skilled nursing facility, even for a short time. In line with this goal, S.F. has eagerly and actively participated in twice-daily physical therapy sessions. She has informed the nursing staff that she has a low tolerance for pain and asks for the oral pain medication 30-45 minutes before each therapy session. Initially, S.F. tolerated ROM exercises and limited mobility training well with this “pain premedication” regimen. However, upon standing and attempting gait training on postoperative day three, S.F. experienced dizziness, diaphoresis, and became very short of breath. On the second attempt to stand, the patient experienced syncope.
Derivatives of the opium poppy have been used to relieve severe pain for hundreds (possibly thousands) of years. Morphine, the prototypic opioid agonist, does so with remarkable efficacy. This alkaloid (named after Morpheus, the Greek god of dreams) is extracted from crude opium, which is obtained from the opium poppy seedpod. Morphine remains the standard against which all drugs that have strong analgesic action are compared in terms of efficacy and potency. Opioids include the natural and semisynthetic alkaloid derivatives from opium, synthetic surrogates whose actions are blocked by the nonselective antagonist naloxone, and the endogenous peptides that interact with several opioid receptor subtypes. Although the term narcotic is often used interchangeably with opioid, use of the term narcotic originally referred to any sleep-inducing medication. In the United States, usage of the term narcotic has shifted more toward describing legal and regulatory scheduling of opioids.
Analgesic drug therapy and many physical therapy interventions are aimed at the same outcome: pain relief. Individuals participating in rehabilitative therapy are frequently taking analgesic drugs—especially nonsteroidal anti-inflammatory drugs (NSAIDs) and opioids. The NSAIDs (Chapter 34) have significantly lower maximal analgesic efficacy than the opioids, but have no addiction liability. While many NSAIDs are available over the counter for mild to moderate pain relief, opioids are usually prescribed to manage more severe or constant pain. For optimal pain relief and to achieve ...