Is naltrexone (opioid receptor antagonist) effective for treating long COVID (Post-Acute Sequelae of SARS-CoV-2 infection)?

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Last updated: August 26, 2025View editorial policy

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Low-Dose Naltrexone for Long COVID

Low-dose naltrexone (LDN) shows promise for treating long COVID symptoms, particularly neuroinflammation, fatigue, and pain, though larger randomized controlled trials are still needed to confirm its efficacy.

Evidence for LDN in Long COVID

Low-dose naltrexone has emerged as a potential treatment option for long COVID based on several lines of evidence:

  • The Nature Reviews Microbiology guideline (2023) identifies LDN as a promising treatment for neuroinflammation in long COVID patients, noting it has been effective for subsets of patients 1
  • A recent pilot study (2024) demonstrated significant improvements in quality of life and fatigue scores after 12 weeks of LDN treatment (4.5 mg/day) in patients with persistent post-COVID fatigue 2
  • A pre-post interventional study (2022) found LDN to be safe in long COVID patients, with improvements in 6 of 7 measured parameters including energy levels, pain, concentration, and sleep disturbance (p≤0.001) 3

Mechanism of Action

LDN may help long COVID patients through several mechanisms:

  • Blunting excessive innate immune responses and Toll-like receptor signaling 4
  • Reducing inflammatory cytokines including IL-1, TNF-α, and interferons 4
  • Addressing immune-mediated thrombotic complications that may underlie some long COVID symptoms 4

Dosing and Administration

  • Typical dosing starts low (1 mg daily) with gradual up-titration to 4.5 mg daily or maximum tolerated dose 5
  • Treatment duration of at least 12 weeks may be needed to observe significant benefits 2

Safety Profile

  • LDN is generally well-tolerated with a favorable safety profile 3
  • Most common adverse events are mild and include:
    • Diarrhea (reported in about 5% of patients) 3
    • Fatigue (which may temporarily worsen before improving) 3
    • These side effects can often be managed with dose adjustments 2

Important Considerations

  • LDN should not be used in patients taking opioid medications due to potential interactions 5
  • Patients with significant liver disease should avoid LDN 5
  • LDN is currently used off-label for long COVID, as there are no FDA-approved treatments specifically for this condition 6

Complementary Approaches

For comprehensive management of long COVID symptoms, consider combining LDN with:

  • Coenzyme Q10 and D-ribose for mitochondrial support, which may help with fatigue 7
  • Cognitive pacing strategies to manage energy expenditure 7
  • Avoidance of exercise in patients with post-exertional malaise (PEM), as physical activity worsened symptoms in 75% of long COVID patients 1, 7

Current Limitations

The European Society of Clinical Microbiology and Infectious Diseases (ESCMID) notes that evidence remains insufficient to provide definitive recommendations for any intervention in long COVID 1. While preliminary evidence for LDN is promising, larger randomized controlled trials are currently underway to provide more conclusive evidence 5.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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