Low Dose Naltrexone for Chronic Pain: An Underused Option
Low dose naltrexone (LDN) is one of the most underutilized treatments in chronic pain medicine. It's inexpensive, safe, non-addictive, and backed by a growing body of evidence — yet many patients have never heard of it, and many pain physicians don't prescribe it.
I've been using LDN in my practice for several years, and I've been consistently impressed by the results in the right patients. Here's what you need to know.
The Mechanism Is Different from Everything Else
Standard naltrexone (50 mg) is FDA-approved to treat opioid and alcohol dependence — it blocks opioid receptors completely. At one-tenth of that dose (typically 1.5–4.5 mg), taken at bedtime, something different happens.
The brief, partial opioid receptor blockade at night causes the body to temporarily upregulate its own endorphin production — increasing natural pain modulation. But the more important mechanism may be the direct inhibition of microglia — the immune cells of the central nervous system.
Microglial overactivation (neuroinflammation) is increasingly recognized as a core driver of fibromyalgia, CRPS, and many other chronic pain conditions. LDN directly targets this mechanism — which no other widely available pain medication does.
The Evidence
- Fibromyalgia: A Stanford double-blind crossover trial showed significant pain reduction (30% greater than placebo) with excellent tolerability
- CRPS: Case series and clinical experience support meaningful improvement in this neuroinflammatory condition
- Multiple sclerosis: Reduces pain and fatigue; several clinical trials published
- Inflammatory bowel disease: One of the strongest evidence bases; reduces Crohn's disease activity
- Chronic neuropathic pain: Including post-surgical and post-herpetic neuralgia
Starting LDN
LDN is prescribed off-label for chronic pain. Because it's not commercially available in the required doses, it's obtained through a compounding pharmacy — typically $30–60 per month.
I start patients at 1.5 mg at bedtime and increase slowly to 3–4.5 mg over several weeks. Side effects are minimal — the most common is vivid dreams during the first 1–2 weeks, which typically resolve.
Important: LDN cannot be used concurrently with opioid medications, as it will trigger withdrawal. If you're on opioids, a transition plan is needed first.
Who Is a Good Candidate?
LDN is particularly appropriate for:
- Fibromyalgia patients with central sensitization features
- CRPS patients as part of multimodal management
- Patients with chronic pain and autoimmune/inflammatory overlap
- Patients who want to avoid or reduce opioid exposure
- Patients who have failed multiple standard pain medications
The Bottom Line
LDN is not a miracle cure, but it fills a unique niche in chronic pain management — addressing neuroinflammation in a way no other available medication does. For the right patient, it can be a genuine game-changer.
Call 516-492-3100 to discuss whether LDN is appropriate for your condition.