Naltrexone and Long Covid

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Naltrexone for Long COVID: Usage and Effects

Naltrexone is a Food and Drug Administration (FDA) approved medication for the treatment of opioid use disorder (OUD) and alcohol use disorder (AUD). However, low doses of the medication have been administered to Long COVID patients as well, and the results are promising. Read on to know more about naltrexone and how it may benefit individuals with Long COVID. However, before we get to Naltrexone’s benefits in treating Long COVID, let’s understand a little about how it works.

How Naltrexone works

Naltrexone is one of the most popular medications for treating AUD and OUD as unlike several other medications, it is not addictive nor an opioid. Addictive medications for treating these conditions have been criticized. While they may successfully treat AUD and OUD, they are likely to hinder the recovery of individuals due to their withdrawal symptoms. Individuals are likely to experience withdrawal symptoms after discontinuing use.

The medication works by blocking the sedative and euphoric effects of various opioids like codeine, morphine, and heroin. By binding and blocking opioid receptors, Naltrexone suppresses and reduces opioid cravings. The biggest advantage of treating AUD and OUD with Naltrexone is that there is no diversion and/or abuse potential.

What is Long COVID and what are its symptoms?

Many individuals who tested positive for COVID-19 successfully recovered and did not report any problems post-recovery. However, for some others, some symptoms of COVID-19 continued despite testing negative for the disease following recovery – this is what came to be known as Long COVID.

Long COVID patients have reported a wide variety of symptoms, which include the following:

  • Fever
  • Fatigue
  • Breathing difficulties
  • Muscle or joint pain
  • Neurological symptoms like concentration issues, sleeping difficulties, anxiety, and headaches
  • Rashes
  • Menstrual cycle changes
  • Blood vessel problems and blood clots
  • Digestive systems
  • Chest pain

While medical experts are yet to determine what exactly triggers Long COVID, there is a growing consensus regarding its cause. The experts believe that people who suffered from severe COVID-19 infections experienced organ damage. The symptoms associated with Long COVID may be the result of the damaged organs not functioning the way they are meant to.

Naltrexone for Long COVID: What research has shown so far

study conducted in the Mater Misericordiae University Hospital (MMUH) in Dublin, Ireland attempted to find out whether low doses of Naltrexone can be beneficial for treating Long COVID patients. It involved approximately 300 patients recruited from the Infectious Diseases Directorate’s ‘COVID clinic’, who were administered 1 mg of Naltrexone every day for a month. The following month, the dosage was increased to 2 mg, and during the third month, patients received 3 mg of the drug daily.

All recruited patients were assessed via questionnaires prior to the study’s commencement and after it was concluded. The questionnaires focused on the 7 following clinical status components:

  • Sleep
  • Concentration
  • Pain/discomfort
  • Energy levels
  • Limitations in daily living activities
  • Perception of overall recovery

After the 3-month period during which patients were administered low doses of Naltrexone, they reported improvements in 6 components. The biggest improvements were reported in pain and discomfort levels. All in all, it’s safe to say that Naltrexone has shown promising results so far in terms of treating Long COVID. However, the study also concluded that more research is necessary to determine the efficacy and safety of Naltrexone for Long COVID treatment.

How does Naltrexone improve Long COVID symptoms?

To understand how naltrexone can play a positive role in improving long COVID symptoms, it’s essential to understand COVID-19’s mechanism. The entry of coronavirus into host cells is dependent on the glycoprotein on the cells’ surfaces. The cell’s Receptor Binding Domain (RBD) interacts with a host cell receptor known as Angiotensin Converting Enzyme-2 (ACE2). Once the infection is initiated, it induces a cytokine storm, which leads to organ inflammation.

This is where naltrexone can suppress the cytokine storm and reduce the subsequent inflammatory damage sustained by the organs. Naltrexone can disrupt the interaction between the RBD and ACE2 receptors.

Potential side effects of Naltrexone

Despite being a potential game-changer in Long COVID treatment, Naltrexone may induce certain side effects in users. Some of the side effects are considered common, while there is also a possibility of experiencing severe side effects. The most common side effects of Naltrexone include the following:

  • Abdominal discomfort
  • Sleeping difficulties
  • Joint/muscle pain
  • Dizziness
  • Headaches
  • Anxiety
  • Fatigue
  • Rashes
  • Appetite loss
  • Liver problems
  • Nausea

Most of these side effects are mild and self-limiting, and they are typically resolved on their own as the body adapts to the medication. However, you should seek immediate medical attention if you experience one or more of the following side effects, which are more severe:

  • Severe depression
  • Serious allergic reactions
  • Pneumonia

Safe Naltrexone use: The best practices

In this penultimate section of the post, we will take you through some safe practices when it comes to Naltrexone use. These practices can go a long way toward ensuring that Naltrexone use does not jeopardize your health:

  • Avoid consuming certain substances: During Naltrexone treatment, it’s recommended to avoid illegal drugs, and prescription opioids like codeine and tramadol. As Naltrexone blocks the effects of opioids, overconsumption can result in overdose and subsequently, coma or even death. In terms of combining Naltrexone and alcohol, it’s important to remember that Naltrexone will only block the feelings of euphoria induced by alcohol use. However, it has no effect on the motor impairment caused by excess alcohol consumption.
  • Consume only as much as recommended by your doctor: People with moderate-severe Long COVID symptoms may feel the urge to consume greater doses of Naltrexone to treat the symptoms. However, excessive consumption of Naltrexone can have a devastating impact on the liver. That’s why people who have been diagnosed with liver-related conditions such as severe liver disease and hepatitis should steer clear of the drug.
  • Spare some thought for drug interactions: Starting new over-the-counter and prescription medication when you are on Naltrexone is not a good idea. Also, refrain from using dietary and/or herbal supplements. Before starting any new medication or supplement during Naltrexone use, it’s best to consult your doctor to know if there is any interaction potential. For instance, Naltrexone’s effects render the opioid-based medication ineffective. So, for example, if you need to use an analgesic, buy a non-opioid analgesic.


Naltrexone’s promise of being a treatment for Long COVID is certainly something that inspires optimism. However, it’s still too early to hand out any verdicts as research has been limited. As the coronavirus mutates with more variants proliferating, it would be interesting to see if Naltrexone can keep up with the changes and emerge as an effective Long COVID treatment. However, nothing is guaranteed as further research may reveal things about the drug that are still unknown.