Low Dose Naltrexone for Chronic Pain Management

Primary Indications

The American Academy of Pain Medicine recommends low-dose naltrexone (LDN) at 1.5-4.5 mg nightly for chronic neuropathic pain conditions, particularly fibromyalgia, complex regional pain syndrome, and painful diabetic neuropathy 1, 2
LDN demonstrates the strongest evidence for neuropathic pain syndromes, including fibromyalgia, with a significant decrease in pain and improved satisfaction with life compared to placebo in a randomized controlled trial (RCT) of 31 patients 1, 2
The Canadian Association of Gastroenterology recommends against using naltrexone to induce or maintain symptomatic remission in Crohn's disease, with a conditional recommendation and low-quality evidence 3

The standard LDN dosing protocol for chronic pain starts at 1.5 mg at bedtime with gradual bi-weekly increases of 1.5 mg to a final maximum dose of 4.5 mg taken at bedtime 1, 2
The initial dose is 1.5 mg nightly, with titration increases of 1.5 mg every 2 weeks, and a target dose of 4.5 mg nightly 4

Patients requiring opioid therapy for pain management should not be prescribed LDN, as it will block opioid analgesia even at low doses 4
Patients currently taking opioids must be opioid-free for a minimum of 7-10 days before initiating any dose of naltrexone 4
LDN should be held for 2-3 days before elective procedures if opioids will be needed for pain control 4

Common side effects of LDN are generally mild and well-tolerated, including tachycardia 2, drowsiness 1, and dizziness 1

Naltrexone 50 mg daily shows moderate-quality evidence for maintaining abstinence in alcohol use disorder, with a 31% absolute probability vs 25% for placebo 6, 7, 8
The naltrexone-bupropion combination (8 mg naltrexone + 90 mg bupropion per tablet) is used for obesity, not chronic pain, and should not be confused with LDN protocols 5, 4