Can low‑dose naltrexone (LDN) from a 0.5‑mg to 4.5‑mg titration pack, currently at 2 mg, be stopped abruptly despite side effects?

Can Low-Dose Naltrexone at 2 mg Be Stopped Abruptly?

Yes, low-dose naltrexone at 2 mg can be stopped abruptly without requiring a taper, as the FDA warnings about withdrawal and discontinuation risks apply specifically to standard-dose naltrexone (50 mg) used for opioid/alcohol dependence, not to the low-dose formulations (1-5 mg) used for chronic pain or inflammatory conditions. 1

Critical Distinction Between Standard and Low-Dose Naltrexone

• Low-dose naltrexone (LDN) refers specifically to naltrexone used at 1-5 mg daily, which is approximately 1/10th of the standard 50 mg dose used for opioid and alcohol dependence 2
• The FDA warnings about precipitated withdrawal, hepatotoxicity, and discontinuation risks in the drug label are based on standard-dose naltrexone (50 mg) for substance use disorders, not low-dose protocols 1
• At low doses (1-5 mg), naltrexone works through different mechanisms—transiently blocking opioid receptors to upregulate endogenous opioid signaling and modulating inflammatory pathways—rather than providing sustained opioid receptor blockade 3

Why Abrupt Discontinuation is Safe at Low Doses

• The FDA warnings about "vulnerability to opioid overdose after discontinuation" specifically address patients treated for opioid dependence with standard 50 mg doses, where the concern is loss of opioid tolerance 1
• For patients using LDN at 2 mg for chronic pain or inflammatory conditions (not opioid dependence), there is no physiological dependence created that would require tapering 3, 4
• Clinical studies of LDN for fibromyalgia, chronic pain, and inflammatory conditions show patients can discontinue without withdrawal symptoms or adverse events related to stopping the medication 4, 5

Managing Side Effects at Current Dose

• Common side effects of LDN include vivid dreams, drowsiness, dizziness, and nausea, reported in approximately 32% of patients 4
• If side effects are intolerable at 2 mg, the patient can either stop immediately or reduce to 1.5 mg or 1 mg for a few days before stopping, though this is for comfort rather than medical necessity 6
• The medication use evaluation showed LDN was generally well-tolerated with most adverse effects being mild and self-limiting 4

Important Caveats

• Do not confuse this with standard-dose naltrexone discontinuation: The FDA label warnings about tapering apply to the 50 mg dose used for substance use disorders, where abrupt discontinuation increases overdose risk if patients return to opioid use 1
• Verify the patient is not taking LDN for opioid dependence: If the patient has underlying opioid use disorder being treated with naltrexone, different discontinuation protocols apply 7
• The naltrexone-bupropion combination (8 mg naltrexone per tablet) used for obesity should not be stopped abruptly and requires tapering over at least 1 week, but this is a different formulation than LDN 6

Practical Recommendation

• The patient can stop the 2 mg dose immediately without tapering 3, 4
• Monitor for return of underlying symptoms (pain, inflammation) that LDN was treating, not withdrawal symptoms 4
• If the patient wishes to retry LDN in the future, starting at 0.5 mg or 1 mg and titrating more slowly may improve tolerability 6, 8