Chronic Pain & Opioid Stewardship

Chronic noncancer pain: nonopioids first

Multimodal first. For chronic noncancer pain, maximize nonpharmacologic and nonopioid therapy before considering an opioid. Opioids are not first-line and add little benefit in chronic low back pain, headache, or fibromyalgia. Treatment goals should be improved function, not zero pain.

Acetaminophen and NSAID limits. Acetaminophen is capped at 3–4 g per day, and about 2 g with liver disease or regular alcohol use, because it is hepatotoxic in overdose. NSAIDs risk GI bleeding, acute kidney injury (avoid them in CKD), fluid retention, and cardiovascular events; use them cautiously in older adults and in heart failure. Topical NSAIDs for localized joint pain, or a PPI for patients at GI risk, reduce harm.

Neuropathic pain (diabetic neuropathy, postherpetic neuralgia) does not respond to acetaminophen or NSAIDs. Use one of three adjuvant classes:

• SNRIs: duloxetine or venlafaxine. Duloxetine treats painful diabetic neuropathy and coexisting depression, a favorite two-for-one answer.
• TCAs: nortriptyline or amitriptyline. They are anticholinergic and can prolong the QRS, so be cautious in older adults and in heart disease.
• Gabapentinoids: gabapentin or pregabalin. They cause sedation and dizziness; reduce the dose in renal impairment.

Topical lidocaine or capsaicin helps localized neuropathic pain such as postherpetic neuralgia. Fibromyalgia responds to duloxetine, milnacipran, or pregabalin plus graded exercise.

Prescribing opioids safely: CDC 2022 guardrails

Before and during therapy. Check the state prescription drug monitoring program (PDMP) before starting and periodically afterward, and consider urine drug testing at the same points. Start with the lowest effective dose of an immediate-release (not extended-release) opioid. For acute pain, a few days' supply is usually enough. Reassess benefits and harms within 1–4 weeks of starting or raising the dose, and regularly thereafter.

Soft guardrails. The 50 and 90 morphine milligram equivalent (MME) thresholds come from the 2016 guideline; the 2022 update softened them into guideposts rather than rigid caps, keeping only a pause to reassess before exceeding about 50 MME/day: individualize, and never use them to justify abrupt cutoffs. Methadone and transdermal fentanyl have nonlinear, high MME conversions, so a small dose increase can be a large MME jump.

Never pair opioids with benzodiazepines. Their additive respiratory depression drives overdose deaths. Co-prescribe naloxone whenever overdose risk is higher, for example ≥50 MME per day, a concurrent benzodiazepine, or a history of overdose or substance use disorder.

Treatment agreement and drug testing. Before chronic opioid therapy, screen for misuse risk, sign a written treatment agreement, and set expectations: a single prescriber and pharmacy, and possible periodic urine drug testing. An unexpected result prompts reassessment, not automatic dismissal. No prescribed opioid in the urine raises concern for diversion; an illicit drug raises concern for a substance use disorder that needs treatment.

Tapering. Never stop opioids abruptly in a physically dependent patient: it precipitates withdrawal and crisis and can push the patient to illicit supply and overdose. Taper gradually and individually, for example about 10% per month for long-term users, with the patient involved in the plan. Reserve a rapid taper for a serious safety issue such as an overdose, and offer OUD treatment if a use disorder emerges.

Tolerance, dependence, addiction, and pseudoaddiction

Opioid use disorder (DSM-5). At least 2 of 11 criteria within 12 months, across impaired control, craving, continued use despite harm, and social impairment. Severity is mild with 2–3 criteria, moderate with 4–5, and severe with 6 or more. Tolerance and withdrawal do not count when opioids are taken as prescribed under medical supervision.

Medications for opioid use disorder (MOUD)

Buprenorphine binds the μ receptor more tightly than full agonists and displaces them. Given while a full agonist still occupies the receptors, it abruptly lowers net receptor activation and precipitates withdrawal. The naloxone in the combination product is poorly absorbed orally and is there to deter injection.

Overdose versus withdrawal

Naloxone can precipitate acute withdrawal. It is also shorter-acting than many opioids, so patients who took methadone or extended-release products need observation and repeat doses or an infusion for recurrent sedation. Flumazenil reverses benzodiazepines, not opioids.