Naltrexone is an FDA-approved medication for opioid use disorder (OUD) and alcohol use disorder. It was first discovered in 1969 – over 50 years ago! Yet, it did not meet its claim to fame until 1972, when the United States Congress passed the Drug Abuse Office and Treatment Act to combat substance misuse.

Newer research shows that low-dose naltrexone (LDN) can also treat many other conditions. Here we discuss what LDN is, how it works, and what to avoid when taking it.

What is Naltrexone, and What is it Used For?

Naltrexone is an opioid antagonist. This means it works by blocking the opioid and endorphin receptors in the body. As a result, users experience lesser cravings for substances such as opioids and alcohol.

Research shows naltrexone users have a higher percentage of opioid-free weeks than those taking a placebo. On top of that, up to 36% of OUD patients using naltrexone report complete opioid abstinence.

Similarly, clinical trials show twice as many alcohol-dependent patients can abstain from alcohol on naltrexone compared to placebo. 

How to Take Naltrexone?

Naltrexone is available in two forms:

  • A 50 mg oral tablet

  • A 380 mg intramuscular (IM) injection

Healthcare professionals prefer the IM injection even though it's more painful for two reasons:

  • Its effects last for one month instead of only a few days, as with the oral tablets. Thus it will work in patients who are non-compliant with daily medications.

  • It is the preferred option for patients who cannot swallow the oral formulation.

How is Naltrexone Dosed?

Naltrexone dosing differs based on the formulation. 

For instance, dosing of the oral tablet can range between 25 and 100 mg depending on the patient’s substance history and health. Doctors usually begin the treatment at a dose of 25 mg and increase it steadily as long as users do not experience withdrawal.

On the other hand, healthcare providers administer the IM injection monthly in a fixed 380 mg dose.

What is Low Dose Naltrexone, and How Does it Work?

Low dose naltrexone (LDN) refers to naltrexone doses between 1 to 5 mg. LDN works in three main ways:

  • By triggering the release of 'feel good' hormones in the brain

  • By limiting the production of inflammatory chemicals in the body

  • By regulating natural opioid production

What Are Low Dose Naltrexone Uses?

Given its diverse mechanism of action, healthcare professionals use LDN off-label — with promising results — for many conditions. These include:

  • Fibromyalgia

  • Chronic fatigue syndrome

  • Chronic pain

  • Autoimmune conditions such as rheumatoid arthritis, multiple sclerosis, and Crohn's disease

  • Obesity

  • Cholestatic pruritus

  • Depression

  • Post-traumatic stress disorder (PTSD)

  • Cancer

What to Avoid When Taking Low Dose Naltrexone

LDN has a low risk of side effects. Additionally, most of these are mild and subside on their own. However, while rare, more serious adverse effects — such as an allergic reaction — can occur. 

Doctors recommend avoiding the following when taking LDN to lower the risk of side effects:

Opioids and Alcohol

Patients starting naltrexone treatment should be opioid and alcohol-free for a minimum of 7 to 10 days. Beginning naltrexone while still on opioids or alcohol can lead to withdrawal symptoms. These include

  • Anxiety

  • Sleeplessness

  • Fever

  • Sweating

  • Flu-like symptoms

  • Hot or cold flushes

  • Muscle aches and twitches

  • Nausea and vomiting

  • Diarrhea

  • Stomach pain

Certain Medications

Some common medications contain opioids and alcohol; thus, users must avoid them when taking LDN. Examples include:

  • Opioid analgesics, for instance, hydrocodone, oxycodone, codeine, fentanyl, and tramadol

  • Cough and cold remedies such as Phenergan or promethazine

  • Antidiarrheal medication

What Health Conditions Put You at Risk When Taking LDN?

The liver metabolizes naltrexone while the kidney handles its elimination from the body. Thus, patients with kidney and liver problems should avoid using LDN. In addition, patients who do not suffer from these conditions but develop yellow discoloration of their eyes must visit their physician promptly.

Frequently Asked Questions (FAQs) About Low Dose Naltrexone?

What Happens if you Drink Alcohol While Taking Naltrexone?

Naltrexone suppresses the euphoric feelings of alcohol. Thus, users may ingest increased quantities of alcohol to achieve the same effect. This increases their risk of overdose.

Can You Overdose on Naltrexone?

No. Pharmacists designed naltrexone to ensure patients are unable to overdose on it.

Low Dose Naltrexone May Be The Treatment For You

Are you interested in learning if Naltrexone is suitable for you? If so, contact our Naltrexone doctors to learn more. Rest assured, they have the answers to all your questions.