- Tramadol
- Dual mechanism: serotonin/norepinephrine reuptake inhibition
- Weak mu-opioid receptor agonism
| - Acute and chronic pain: moderate–severe1
- Postoperative pain2
- Neuropathic pain2
| 50–100 mg po q6–8 h | - Nausea, vomiting, constipation, dizziness, headaches
- Serious reactions: seizures, serotonin syndrome
| - Caution if history/risk of seizure
- Avoid abrupt cessation
- Risk of suicidality
- Pregnancy Class C
|
- Clonidine
- Central alpha-2 adrenergic agonist
| - Peripheral neuropathy2
- Postherpetic neuralgia2
- Cancer pain2
- CRPS2
- Postoperative pain2
- Adjuvant in neuraxial and peripheral nerve blocks2
- Opioid withdrawal2
| - 0.1 mg po q12 h weekly titration up to 2.4 mg/day
- 0.1 mg/day transdermal
- Up to 0.6 mg/day
- 30 μg/h epidural infusion
| Hypotension, bradycardia, AV block, dry mouth, drowsiness, sedation fatigue, depression, fever | - Avoid abrupt withdrawal, risk of rebound hypertension
- Pregnancy Class C
|
- Ketamine
- NMDA receptor antagonism
| - Intraoperative and postoperative pain2
- Burn pain2
- Cancer pain2
- Neuropathic pain2
- Opioid-induced hyperalgesia2
| - IV infusion
- Transdermal
- SQ infusion
| In analgesic doses: hypersalivation, anorexia, nausea, elevated BP, hallucinations, withdrawal syndrome (long-term use) | - Black box warnings: emergence reactions—various degrees of psychologic manifestations from pleasant dream-like states to irrational behavior and emergence delirium. The 100 mg/mL concentration of ketamine hydrochloride injection should not be injected intravenously without proper dilution
- Pregnancy Class D
|
Lidocaine- Blocks sodium channels
- Decreases ionic flux through the neuronal membrane
| - Postherpetic neuralgia1
- Local anesthesia, postoperative pain1
- Neuropathic pain2
- Burn pain2
| - Topical: transdermal
- maximum three patches/ 24 h
- IV: various protocols
| | Pregnancy Class C |