Multimodal Analgesia and Chronic Pain

ERAS (enhanced recovery after surgery) protocols, the opioid epidemic, and outcome data have converged on multimodal analgesia as standard of care.

Mechanism: targeting different pain pathways (nociceptor, peripheral nerve, spinal dorsal horn, descending modulation, central sensitization) simultaneously achieves better pain control with lower total opioid dose.

Goal: opioids for breakthrough only, ideally none postop in many ambulatory cases.

Max 4 g/day adult, 3 g/day if liver disease or chronic ETOH, 2 g/day if both.

IV onset 15 min, PO onset 30-60 min — therapeutic equivalence is well-established (IV does NOT outperform PO for routine use).

Multiple trials show ATC scheduling outperforms PRN.

Reduces opioid consumption 20-30% post major surgery.

Almost no contraindications — always include in multimodal plan unless severe liver disease.

IV formulation cost has driven shift back to PO/PR where possible.

Celecoxib 200-400 mg PO (COX-2 selective, less GI bleed but cardiac concern at high dose).

Ibuprofen 400-600 mg PO q6h.

Reduces opioid consumption 25-40%.

Ortho bone-healing concern is weak evidence — surgeon preference varies.

Single-shot or catheter.

Reduces opioid consumption 50-70% in first 24 hr.

Patient satisfaction higher, time to ambulation shorter.

Combine with multimodal IV/PO for the visceral pain component not covered by somatic block.

Catheter pumps allow 48-72 hr coverage for major surgery.

Dose: 0.15 mg/kg IV bolus at induction + 0.15 mg/kg/hr intraoperative infusion + 0.1 mg/kg/hr in PACU; or 0.5 mg/kg in PACU bolus for breakthrough.

Reduces opioid consumption 30-50% in major surgery.

Mechanism: prevents central sensitization + hyperalgesia by blocking the NMDA receptor that mediates wind-up at the spinal dorsal horn.

Anti-depressant effect documented (single-dose can lift depression for days).

At sub-anesthetic doses (≤0.5 mg/kg bolus) dissociative effects are mild and well-tolerated.

Dose: 0.5-1 mcg/kg load over 10 min + 0.2-0.7 mcg/kg/hr maintenance.

Caution: bradycardia + hypotension (especially with bolus loading), avoid in heart block.

Useful for awake fiberoptic intubation, ICU sedation, opioid-sparing major surgery, dental/oral surgery sedation.

Off-label as adjunct in regional blocks (perineural dexmedetomidine prolongs block duration).

Monitor for LAST signs (peri-oral numbness, tinnitus, metallic taste, arrhythmia, seizure) — keep plasma levels <5 mcg/mL.

Avoid in severe hepatic dysfunction, heart block, bupivacaine LAST concurrent risk.

Pregabalin similar.

Magnesium sulfate IV 30 mg/kg load + 10 mg/kg/hr — NMDA antagonist, modest opioid sparing.

Methadone 0.1-0.3 mg/kg at induction — long-duration analgesia for major surgery (NMDA + mu activity) — caution QT, drug-drug interactions.

Esmolol infusion (opioid-sparing in some studies).

Clonidine 1-2 mcg/kg as alternative to dex.

Add multimodal adjuvants aggressively — these patients benefit most.

Anticipate 30-100% HIGHER rescue dose requirements than opioid-naive patients.

Do NOT attempt to detox during the surgical episode — that's an outpatient discussion.

Acute pain service consult often valuable.

OUD on methadone: continue maintenance dose perioperatively.

OUD on buprenorphine: current ASRA/ASAM 2021 guidance favors CONTINUATION over hold-and-bridge in most cases (multimodal + higher-dose full mu agonists for breakthrough); selective holds for major surgery still considered.