Acute pain management in hospitalized adult patients with opioid dependence: a narrative review and guide for clinicians

Clinical Example: Patient on Chronic Opioid Therapy for Chronic Pain

A 64 year-old man was involved in a motorcycle accident and suffered a right distal tibia-fibula fracture and several broken ribs with a secondary pneumothorax. The patient’s past medical history is significant for chronic low back pain for which he states he takes morphine sustained release 30 mg orally every 8 hours and morphine immediate release 15 mg orally four times daily for breakthrough pain. The patient states his pain is much worse than prior to the accident. Trauma surgery requests recommendations on appropriate pain management. What is the best way to manage this patient’s acute pain and communicate with him about his pain management?

When treating acute pain in patients with chronic pain on opioid therapy, it is vital to establish the patient’s baseline pain level and to accurately reconcile the patient’s outpatient daily opioid use. The patient’s prescription record should be verified in the state’s prescription drug monitoring program. On admission, a urine drug test should be obtained to assess for use of other potential illicit substances (eg, cocaine). Patients who test positive for illicit substances are at high risk for a substance use disorder. Management and discharge plans should be as outlined in the above case. It is important to know that the first-tier immunoassay urine toxicology screens used by hospitals test for natural opioids (morphine, codeine, heroin). Semi-synthetic (example, oxycodone) or synthetic (example, fentanyl) opioids are unlikely to be detected and thus the urine drug screen may not be helpful to determine adherence to certain prescription opioids. Gas chromatography/mass spectrometry is the most sensitive and specific type of urine screen and can be ordered to confirm a prescribed opioid if needed.²⁶

Pain management should begin with calculating the TDD of oral opioids that the patient was taking prior to admission, and converting to morphine equivalents. For moderate acute pain, TDD can be increased by 25% to 50%. The revised TDD can then be prescribed as a long-acting opioid every 8 to 12 hours to provide basal analgesia. The dose of additional immediate-release medication available throughout the day to manage breakthrough pain is determined by dividing the new TDD into every 3 to 4 hours as-needed dosing (Table 2).

If severe pain is anticipated, patient controlled analgesia (PCA) is an effective alternative to deliver opioids. The use of PCA allows self-titration, on demand analgesia, and minimizes the likelihood of under-dosing the patient.²⁷ The revised TDD is a useful starting point when calculating the PCA dosage regimen. Ideally, the revised TDD should be prescribed as a long acting oral opioid medication every 8 to 12 hours for basal analgesia, with PCA administered as an as-needed bolus. If a patient cannot tolerate oral medications, PCA can provide continuous infusion of medication to provide basal analgesia, though the risk of oversedation and respiratory depression is increased.²⁸

For our clinical example, we recommend increasing the preadmission TDD of opioids (180 mg morphine equivalents) by 25% (225 mg) and administering as morphine 75 mg sustained-release every 8 hours to provide baseline analgesia and prevent withdrawal symptoms. The acute pain can be managed by initiating morphine PCA without continuous infusion at 0.5 mg bolus every 8 minutes as needed for breakthrough pain or oral morphine 30 mg immediate-release tablets every 3 hours as needed for pain. The patient should be assessed frequently, and naloxone kept readily available. In addition, nonopioid and nondrug treatments should be optimized.

When communicating with patients with underlying chronic pain on chronic opioid therapy, it is important to discuss the treatment plan early, including addressing that they will likely not be pain free during their hospitalization, but rather goals of pain relief and improved function should be established. The plan to change to oral opioid analgesics as soon as possible and importance of multi-modal treatment should be emphasized. The patient should be informed that medication changes are for the short-term only and that the underlying chronic pain will likely remain unchanged.

Clinical Example: Patient on Medication-Assisted Therapy

A 42-year-old woman presents with acute epigastric pain and receives a diagnosis of acute gallstone pancreatitis. She states that her pain is very severe and appears uncomfortable. Her past medical history is significant for heroin addiction, but she has been successfully treated for opioid-use disorder with buprenorphine 16 mg daily for the past three years. What is the best way to manage this patient’s acute pain and communicate with her about her pain management?

Medication-assisted therapies (MATs) for treatment of opioid abuse, which include methadone and buprenorphine (Table 3), have been shown to be effective in helping patients recover in opioid-use disorder, are cost-effective and reduce the risk of opioid overdose.²⁹ However, treatment for acute pain in patients who are receiving methadone or buprenorphine MAT is a challenge because of pharmacokinetic changes that occur with prolonged use. It is important to know that patients receiving opioid agonist MAT are usually treated with 1 dose every 24 to 48 hours and do not receive sustained analgesia.³⁰

In the case of patients on methadone as MAT, the methadone should be continued at the prescribed daily dose and additional short-acting opioid analgesics given to provide appropriate pain relief.^27,31 Because of opioid tolerance, patients receiving MAT often require increased and more frequent doses of short-acting opioid analgesics to achieve adequate pain control.

Buprenorphine is a mu-opioid receptor partial agonist. The partial agonist properties of buprenorphine result in a “ceiling effect” that limits maximal analgesic and euphoric potential. Buprenorphine’s high affinity for the mu receptor also may result in competition with full opioid agonist analgesics, creating a challenge in treating acute pain. Because of the erratic dissociation of buprenorphine from the mu receptor, naloxone should be available and patients should be frequently monitored when the two agents are administered together. Recommendations regarding acute pain management in patients being treated with buprenorphine are largely based on expert opinion. Treatment options include^32-34: