What to avoid when taking Low Dose Naltrexone

Medically reviewed by: Dr Vasilios Silivistris.DipComp. DipCouns. DipSup. MBACP. BA. MA. FRSH. PhD

Date: 10 June 2025

Written and last updated by: Michael Imonirhua

Using Naltrexone for Alcohol Dependence (The Sinclair Method): A Patient’s Guide to Safe Use

At Home Detox UK, we support individuals on their journey to overcome alcohol dependence. For many, The Sinclair Method (TSM), which often involves the medication Naltrexone, is a key part of this journey. Naltrexone, when used as part of TSM, works differently from some other addiction treatments. It’s designed to help you gradually reduce your desire for alcohol by changing how your brain responds to it.

While Naltrexone can be a very effective tool, it’s a powerful medication. To ensure your safety and the success of your treatment, it’s crucial to understand what you should avoid and be cautious about while taking it. This guide is here to walk you through these important safety measures.

The Single Most Important Thing to Avoid: Opioid Medications and Substances

This is the most critical warning for anyone taking Naltrexone. Naltrexone is an opioid antagonist. This means it blocks the effects of opioid drugs in your brain.

If you take any opioid medication or substance while Naltrexone is in your system, you risk a very serious and potentially dangerous reaction called precipitated withdrawal.

What is Precipitated Withdrawal?

Precipitated withdrawal is not like the gradual withdrawal symptoms that can happen when someone stops using opioids. Instead, it’s a sudden, intense, and often much more severe reaction. It happens because Naltrexone quickly strips opioids from the receptors in your brain. Symptoms can appear within minutes and may include:

Severe nausea, vomiting, and diarrhea
Intense stomach pain and cramping
Strong muscle cramps and body aches
Heavy sweating, fever, or chills
Rapid heartbeat and high blood pressure
Severe anxiety, agitation, and panic
In rare, severe cases, seizures

Opioids You Absolutely Must Avoid:

This list includes common prescription painkillers, illegal drugs, and even some medications used in other addiction treatments. Always tell any doctor, dentist, or pharmacist that you are taking Naltrexone before they prescribe or give you any new medication.

Prescription Opioids:
- Codeine (often in cough and pain medications)
- Morphine
- Oxycodone (e.g., OxyContin®, Percocet®)
- Hydrocodone (e.g., Vicodin®)
- Fentanyl (patches, lozenges, or illicit forms)
- Hydromorphone (e.g., Dilaudid®)
- Tramadol
- Meperidine (e.g., Demerol®)
- Buprenorphine (e.g., Suboxone®, Subutex® – also used for opioid addiction treatment, but dangerous with Naltrexone if opioids are still in your system)
Illicit Opioids:
- Heroin
- Illicitly manufactured Fentanyl (often found in counterfeit pills or mixed with other drugs)
Opioid-Containing Medications:
- Some cough syrups (check labels for codeine or dextromethorphan in high doses, which can have opioid-like effects)
- Some anti-diarrhea medications (e.g., high doses of Loperamide)

Crucial: Be Opioid-Free Before Starting Naltrexone

If you have been using any opioids, you must stop taking them for a specific period before you start Naltrexone. This is often called a “washout period.” This period allows the opioids to leave your system so Naltrexone doesn’t cause precipitated withdrawal.

For short-acting opioids (like heroin or most pain pills): Typically 7 to 10 days opioid-free.
For long-acting opioids (like methadone or some slow-release pain medications): Typically 10 to 14 days, or sometimes longer.

Never try to guess this period yourself. Our medical team at Home Detox UK will perform a thorough assessment to ensure it’s safe for you to start Naltrexone. In some cases, a naloxone challenge test might be done by a doctor to make sure opioids are out of your system.

In an Emergency:

Always inform emergency medical staff, surgeons, anaesthetists, and dentists that you are taking Naltrexone. This is vital if you need emergency pain relief or surgery. They will need to use non-opioid pain management options. Carrying a medical alert card or bracelet stating you take Naltrexone is a good idea.

Understanding Alcohol Use with Naltrexone in The Sinclair Method

The Sinclair Method (TSM) has a unique approach to alcohol. Unlike treatments that require you to stop drinking alcohol immediately, TSM involves taking Naltrexone about an hour before you have your first alcoholic drink of the day. You are then meant to continue drinking as you normally would, especially in the early stages of treatment.

How Does Naltrexone Work with Alcohol in TSM?

Blocks Pleasure, Not Intoxication: Naltrexone works by blocking the release of endorphins – the brain’s natural “feel-good” chemicals – that are usually released when you drink alcohol. This means that while you will still feel the intoxicating effects of alcohol (you can still get drunk), the usual pleasure or “buzz” you associate with drinking will be reduced or absent.
Pharmacological Extinction: Over time, by consistently taking Naltrexone before drinking, your brain gradually “unlearns” the association between alcohol and reward. This process is called pharmacological extinction. The craving for alcohol is expected to lessen, and you may find yourself naturally wanting to drink less.
Continued Drinking is Initially Necessary: For TSM to work as intended, you must continue to drink alcohol after taking Naltrexone in the initial phases. The medication needs the presence of alcohol to help “rewire” the brain’s response.

Important Considerations for Alcohol Use:

Liver Health: Both Naltrexone and alcohol are processed by the liver. While the standard doses of Naltrexone used in TSM (e.g., 50mg) are generally considered safe for the liver in healthy individuals, ongoing heavy alcohol consumption can strain the liver. Our medical team will assess your liver function before you start Naltrexone and may monitor it during treatment. It’s important to be honest about your drinking habits.
Goal of TSM: The ultimate goal of TSM is to significantly reduce your alcohol consumption, or for many, to reach a point where they no longer feel the compulsion to drink (extinction). Some people may choose to aim for complete abstinence, while others may find they can drink in a controlled, non-addictive way.
Safety: Remember, Naltrexone does not prevent the impairments that come with being drunk, such as poor coordination or judgment. Always drink responsibly and never drink and drive.

At Home Detox UK, we will guide you on how to use Naltrexone effectively as part of The Sinclair Method, with the aim of helping you regain control over alcohol.

Other Medications and Supplements: Always Discuss with Your Doctor

It’s vital to tell your Home Detox UK doctor about all other medications, herbal remedies, and supplements you are taking before you start Naltrexone, and any time a new one is introduced.

Central Nervous System (CNS) Depressants: Medications like benzodiazepines (e.g., Diazepam (Valium®), Alprazolam (Xanax®), Lorazepam (Ativan®)), sleeping pills, some muscle relaxants, and other sedatives can have additive effects, potentially causing increased drowsiness or sedation. While Naltrexone itself isn’t primarily sedative, caution is advised.
Cough, Cold, and Diarrhea Medications: As mentioned earlier, some over-the-counter and prescription versions of these can contain opioids (like codeine) or substances that act like opioids in high doses (like loperamide). Always check labels carefully and ask your pharmacist or doctor for non-opioid alternatives.
Immunosuppressants/Immunomodulators: If you are taking Naltrexone for alcohol dependence but also happen to have an autoimmune condition and are on medications that suppress or modulate your immune system, discuss this with all your treating doctors. Naltrexone (especially in low doses, which is different from its use in TSM) is sometimes explored for immune modulation, so interactions need consideration by your specialists.
Certain Antipsychotic Medications: There have been reports of lethargy and sleepiness when Naltrexone is used with Thioridazine. Discuss any antipsychotic medications with your doctor.
Herbal Supplements:
- Kratom: This herb has opioid-like properties and should be avoided as it can cause precipitated withdrawal or block Naltrexone’s effectiveness.
- Other supplements with sedative effects (e.g., Kava, Valerian, St. John’s Wort) should be discussed with your doctor.

New Medications: If another doctor prescribes you a new medication, or if you are considering a new over-the-counter drug or supplement, always inform them that you are taking Naltrexone. Our medical team at Home Detox UK will always want to review your full medication list.

Medical Conditions Requiring Caution or Discussion

Certain health conditions may affect how Naltrexone is used or if it’s suitable for you. Your Home Detox UK doctor will carefully review your medical history.

Severe Liver Disease or Acute Hepatitis: Naltrexone is processed by the liver. If you have active, severe liver disease (like acute hepatitis), Naltrexone may not be suitable. Your doctor will assess your liver health, often with blood tests, before and possibly during treatment.
Kidney Disease: Naltrexone and its byproducts are removed from the body by the kidneys. If you have significant kidney problems, your doctor may need to adjust the dose or monitor you more closely.
Pregnancy and Breastfeeding: There isn’t enough research to confirm Naltrexone’s complete safety during pregnancy or breastfeeding. It’s generally not recommended unless the potential benefits clearly outweigh the risks, and this decision must be made in close consultation with your doctor. (Note: TSM requires alcohol consumption, which is also contraindicated in pregnancy).
History of Severe Mental Health Conditions (e.g., severe depression, suicidal thoughts): While Naltrexone is generally considered safe for mental health, in rare instances, it has been associated with depressive symptoms or mood changes. If you have a history of severe mental health conditions, it’s crucial that your mental health is stable and closely monitored by your healthcare providers. Our support team at Home Detox UK provides comprehensive care, which includes monitoring your mental well-being.

Lifestyle Points to Consider

Driving and Operating Machinery: When you first start Naltrexone, some people might experience temporary side effects like dizziness or tiredness. Be cautious with activities like driving or operating heavy machinery until you know how Naltrexone affects you.
Overall Health and Diet: Supporting your recovery with a balanced diet and a healthy lifestyle can make a positive difference. Good nutrition can help your body heal and respond better to treatment. Our team can offer guidance if needed.

Your Journey with Naltrexone and Home Detox UK

Naltrexone, as part of The Sinclair Method, can be a very helpful medication on your path to overcoming alcohol dependence. Its safe and effective use relies on open and honest communication with your Home Detox UK medical team and careful attention to these precautions.

By understanding what to avoid and by discussing your full medical history and all medications with us, you are taking an active and empowered role in your treatment. Your health, safety, and well-being are our top priorities.

Ready to Learn More or Start Your Journey?

If you are considering Naltrexone for Alcohol Use Disorder, want to explore The Sinclair Method, or need a safe, medically supervised detox before starting any new medication, Home Detox UK is here to help.

Call us today for a confidential, no-obligation assessment on 0333 444 0315 or email help@home-detox.co.uk
Visit our website to learn more about The Sinclair Method and our home detox programs.

We are committed to providing you with compassionate, expert support from the comfort and privacy of your own home.