What are the side effects of low-dose naltrexone?
LDN is generally well tolerated at these doses. The most common effects are vivid dreams and disturbed sleep in the first week or two, which usually settle on their own. Headache, nausea, and mild digestive upset are also reported. The most important consideration is not a side effect but an interaction: naltrexone blocks opioid receptors, so opioid pain medication will not work as expected and the combination can be dangerous.
What is common early on
Vivid or unusually memorable dreams and lighter sleep are the most frequently reported effects, typically in the first one to two weeks. They generally resolve as the body adjusts.
If they do not settle, options include taking the dose in the morning instead of at night, or reducing the dose and increasing more gradually. Starting low and titrating slowly reduces this considerably.
Less common effects
Headache, nausea, mild abdominal discomfort, and transient fatigue are reported by some patients. A brief increase in existing symptoms in the first days is sometimes described before improvement.
Serious adverse effects at low doses are uncommon. Naltrexone at high doses carries liver-related cautions; at low doses this is much less of a concern, though your provider may still consider liver function in the context of your history.
The interaction that genuinely matters
Because naltrexone occupies opioid receptors, standard opioid pain medication will not work as expected while you are taking it, and combining them can be dangerous. This is most important around planned surgery, dental procedures, and emergency care.
Tell every provider you see that you are taking LDN, carry that information with you, and discuss timing well in advance of any scheduled procedure. Opioid-containing cough and diarrhoea preparations count too.
More about Low-Dose Naltrexone Therapy
Ask your specific questions directly
Book a consultation with our Folsom naturopathic team to review your medications and discuss whether LDN fits your situation.
Bring recent lab work if you have it — we’ll review it with you.
Medical disclaimer: The information on this page is for general education and is not medical advice, diagnosis, or treatment. It does not list every possible side effect. Low-dose naltrexone is used off-label and long-term safety data for specific uses is still developing. Naltrexone blocks opioid receptors and can interact dangerously with opioid medications — always inform every healthcare provider you see that you are taking it, particularly before any surgery or procedure. Report new or worsening symptoms to your provider.