Low dose naltrexone (LDN) is a compounded medication used off-label to treat fibromyalgia, chronic pain, and inflammatory conditions. Dr. Rainier Guiang, MD, board-certified pain management specialist at University Pain Consultants, answers the most common questions patients ask about LDN.
What is low dose naltrexone (LDN)?
Low dose naltrexone (LDN) uses naltrexone at doses of 1.5 to 4.5 mg per day, roughly one-tenth of the standard addiction-medicine dose. At these micro-doses, naltrexone does not block opioid receptors continuously. Instead, it transiently blocks them for a few hours each night, prompting the body to upregulate endorphin production and modulate microglial activity in the central nervous system. This mechanism is believed to underlie its anti-inflammatory and pain-relieving effects.
How is LDN different from standard naltrexone?
Standard naltrexone (50 mg per day) is used to treat opioid and alcohol use disorders and fully blocks opioid receptors continuously. LDN at 1.5 to 4.5 mg works through a completely different mechanism: intermittent, partial receptor blockade that paradoxically increases opioid sensitivity and reduces neuroinflammation. LDN does not cause sedation, weight gain, or the emotional blunting sometimes associated with standard-dose naltrexone.
What is the evidence for LDN in fibromyalgia?
The most rigorous evidence comes from double-blind, placebo-controlled trials at Stanford University showing statistically significant reductions in fibromyalgia pain, fatigue, and quality-of-life scores in LDN-treated patients compared to placebo. Responders in those trials showed approximately 30 percent reduction in overall symptom burden. Additional trials from the UK and Israel support LDN’s effect on pain and cognitive symptoms in fibromyalgia. The existing evidence base is more robust than for many treatments currently used in fibromyalgia management.
What other conditions can LDN help with?
Beyond fibromyalgia, LDN has emerging evidence for Crohn’s disease, multiple sclerosis, complex regional pain syndrome (CRPS), lupus, chronic Lyme disease, and long COVID. Its mechanism, reduction of microglial activation and central neuroinflammation, is relevant to a wide range of chronic inflammatory and autoimmune conditions. Dr. Guiang will discuss whether your specific diagnosis falls within the current evidence base.
How long does it take for LDN to work?
LDN typically requires 4 to 12 weeks of consistent use before meaningful pain relief is apparent. We start patients at a low dose (1.5 mg) and titrate upward slowly, usually increasing by 1.5 mg every 2 to 4 weeks, to minimize the most common early side effect of vivid dreams. We recommend a minimum 3-month trial before concluding whether LDN is working for you.
What are the side effects of LDN?
LDN is generally very well tolerated. The most commonly reported side effect, especially during the first 2 to 4 weeks, is vivid or unusual dreams, which typically resolve with continued use or a brief dose reduction. Occasionally patients report mild nausea or headache at initiation. Unlike most pain medications, LDN does not cause sedation, cognitive impairment, weight gain, or physical dependence. It is not habit-forming and does not cause withdrawal.
Can I take LDN if I am on opioid pain medication?
No. LDN cannot be used concurrently with opioid medications, including tramadol. Because naltrexone is an opioid antagonist, even at low doses it can precipitate acute withdrawal in a person taking opioids regularly. Patients who wish to try LDN and are currently on opioids need to complete a supervised opioid taper first. Dr. Guiang can discuss a structured weaning protocol for appropriate candidates.
Is LDN covered by insurance? Where is it obtained?
Because naltrexone is FDA-approved only in its standard dose form, the low-dose formulation is compounded by a specialty pharmacy. Insurance typically does not cover it. Monthly cost from a reputable compounding pharmacy ranges from approximately $30 to $60 per month, making it one of the most cost-effective chronic pain treatments available. We provide prescriptions to compounding pharmacies we trust and can guide you on sourcing.
Is LDN FDA approved?
Naltrexone itself is FDA-approved for opioid and alcohol use disorder at 50 mg. LDN, the use of naltrexone at 1.5 to 4.5 mg for pain and inflammatory conditions, is prescribed off-label, which is legal and common in medicine. Off-label prescribing accounts for roughly 20 percent of all prescriptions written in the US and is standard practice when evidence supports benefit and the safety profile is established. The FDA has not disapproved LDN; no company has funded the large trials required for a new indication approval because naltrexone is generic.
Ask about LDN at your next visit
University Pain Consultants serves patients throughout the Inland Empire from our Riverside and Menifee locations. Call 951-900-3253 or request an appointment online with Dr. Guiang to discuss whether LDN is appropriate for your condition.
