Opioid use disorder

Opioid use disorder

Anesthetic relevance	High
Anesthetic management	Use non-opioid pain adjuncts (regional, GABA agonists, NSAIDs) and higher dosing of full mu receptor agonist opioid analgesics (e.g. fentanyl, hydromorphone)
Specialty	Pain
Signs and symptoms	N/A
Diagnosis	N/A
Treatment	N/A
Article quality
Editor rating	In development
User likes	2

This article focuses primarily on management considerations for patients on methadone or Suboxone therapy.

Epidemiology

According to the 2019 Substance Abuse and Mental Health Administration National Survey on Drug Use and Health, 5.7 million people (2.1 percent of people aged 12 or older) in the US were estimated to have used heroin at some point in their lives while 431,000 (0.2 percent) reported use in the last month. Illicit fentanyl and prescription drug misuse have also contributed to rising rates of opioid overdose deaths.

Anesthetic implications

Patients with opioid use disorder on maintenance therapy with methadone or Suboxone (buprenorphine-naloxone) are at high risk of inadequately controlled pain post-procedure due to low dosing or slow titration. Additionally, patients with poorly managed pain are at risk of prolonged hospital stays, increased cravings, and potential relapse.

Pathophysiology

Buprenorphine is a partial mu-opioid receptor agonist and kappa-opioid receptor. It is unique in that its action at the mu-opioid receptor can block binding of other opioids. Methadone is a synthetic long-acting mu-opioid agonist that similarly binds and occupies receptor.

Anesthetic management

Preoperative optimization

Patients can continue to receive adequate pain control peri-operatively while continuing on their home opioid agonist therapy. The dose of methadone or buprenorphine has implications for the risk of opioid tolerance and increased post-operative pain. According to UCSF guidelines for perioperative management of buprenorphine, for example, patients on a high dose of buprenorphine (>8 mg/day) should consider gradual dose reduction prior to elective surgery. At doses lower than 8 mg/day, buprenorphine can be continued through procedure day and day of discharge. Similarly, it is recommended that patients on methadone continue their home dosing peri-operatively[1].

Non-opioid agents such as Tylenol and gabapentin/pregabalin. A shared neuro-inflammatory and central sensitization process akin to that of neuropathic pain may explain the cross-benefit of gabapentin in patients with opioid-induced hyperalgesia.

Intraoperative management

Regional anesthesia techniques (including continuous epidural and peripheral nerve catheters) should be strongly considered in a non-opioid driven anesthetic. Ketamine is a useful adjunct due to its useful effect of increasing opioid sensitivity when run at low dose rates (0.3 mg/kg/hr). Providers should consider Toradol and redosing of Tylenol in longer procedures.

Otherwise, the use of full mu-opioid receptor agonists (fentanyl, hydromorphone) remain important to the management of intraoperative pain. Providers should consider scheduled dosing throughout the procedure balancing the risk of hypotension and respiratory depression seen older patients, those with OSA, and patients with end-organ failure.

Postoperative management

Consider continuing methadone and buprenorphine as part of the post-operative pain management plan. Buprenorphine is unlikely to cause respiratory depression and causes less drug euphoria. Naloxone should not be co-administered due to the risk of causing acute withdrawal.

Providers should continue typical regimens for mild-severe pain post-op (oxycodone, fentanyl, hydromorphone), however higher than normal starting doses of opioids may be required. The typical calculation of milligram morphine equivalents (MME) do not give an accurate sense of equivalent dosing.

Consider post-operative stay in the ICU for pain management and consultation of in-house pain service.