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Answers to Some FAQs on Low-Dose Naltrexone (LDN)

Low dose naltrexone (LDN) is a compounded medication that has shown benefit for reducing fibromyalgia pain in several studies.

What is a typical dosage titration for LDN? The most common practice is to prescribe LDN at 1.5mg at bedtime for 14 days, then 3mg at bedtime for 14 days, then 4.5mg at bedtime ongoing. If patients have side effects at the 4.5mg dosage, I back them down to 3mg dosage.

What are common side effects of LDN and what can I do about them? It is a pretty well tolerated treatment, but patients do report headaches, insomnia, and vivid dreams that usually improve within a few weeks. If insomnia is a problem, dosage can be changed to morning. Some patients do report anxiety as a side effect from LDN, and in that case I usually lower the dosage and add CBD tincture.

How long does LDN take to work for pain? I have seen patients start to get benefit at about 2–3 weeks, but maximum effect is seen at around two months. I have patients try it for three months (first month titrating up dosage and then two full months on 4.5mg dosage) before giving up on it. When using ultra low-dose naltrexone (ULDN) or when patients are also taking opioids, it seems to take longer to get benefit. In that case I might have them take it for four full months before judging effectiveness.

Is LDN an opioid? Is it a controlled substance? LDN is not an opioid and is not a controlled substance. It is an opiate blocker and is used in regular dosages (50mg) to help patients stop abusing alcohol and opioids. However, at lower dosages it has been found to have anti-inflammatory effects, especially in the brain.

Why won’t my doctor prescribe it for me? Most western doctors are only familiar with naltrexone’s usage for addictions, thus are unwilling to consider using it for other indications. Plus, since LDN is a cheap and generic drug, there are no drug companies to fund the kind of large studies that will get doctors’ attention. You will need to find and bring the right research articles to your doctor, and I have made that easy for you by providing you with the correct reference in The FibroManual. You can also find a list of doctors that do prescribe LDN at

What is a compounded medication? A compounded medication is a customized dosage of a medication (or mixtures of medicines) made by a specialty pharmacy called a compounding pharmacy. To find a reputable compounding pharmacy, visit

What other conditions can LDN treat? LDN is being studied and clinically used for many chronic pain and inflammatory conditions including multiple sclerosis, Complex Regional Pain Syndrome, Crohn’s disease, hypothyroidism, and several other conditions. You can learn more in The LDN Book.


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