Naltrexone at a glance
Naltrexone is a prescription medicine used in the management of alcohol dependence and opioid dependence. It is not an opioid and does not produce opioid-like effects. Treatment should be planned with a clinician who can assess medical history, current substance use, and treatment goals.
In Norway, naltrexone is generally supplied under prescription controls. A legitimate pharmacy should verify the prescription and confirm that the medicine is suitable for the individual patient. This process supports safe use and helps identify important contraindications.
Naltrexone works best as part of a broader treatment plan. Counselling, social support, and follow-up care can be important alongside medicine. The medicine does not replace emergency support for overdose, severe withdrawal, or acute mental-health concerns.
Active ingredient and medicine forms
The active ingredient is naltrexone hydrochloride. It belongs to a group of medicines called opioid antagonists. These medicines block specific opioid receptors in the brain and other tissues.
Oral naltrexone tablets are the form most commonly encountered in routine treatment. Strengths and pack sizes can differ between manufacturers and authorised suppliers. A pharmacist can confirm the exact presentation supplied for a particular prescription.
Long-acting injectable naltrexone is available in some health systems, but access and authorisation differ by country. It must be administered by an appropriately trained healthcare professional. It should not be substituted for tablets without prescriber guidance.
How naltrexone was developed
Naltrexone was developed through research into compounds that block opioid receptor activity. It followed earlier work on opioid antagonists, including naloxone. Its longer duration of action made it useful for continuing treatment rather than emergency reversal alone.
Researchers identified that opioid receptors are involved in the effects of opioid medicines and, indirectly, in alcohol reward pathways. This led to clinical investigation of naltrexone for substance-use disorders. Its use has since been incorporated into selected evidence-based treatment approaches.
Development of the medicine does not mean that it is appropriate for every person with alcohol or opioid problems. Individual response, liver health, current opioid exposure, and treatment preferences all matter. A clinician should determine whether expected benefits outweigh possible risks.
What naltrexone is used for
Naltrexone may be prescribed to help prevent relapse to opioid use after a person has completed opioid withdrawal. It blocks the effects of opioid medicines and illicit opioids. Starting it too soon after opioid use can trigger severe precipitated withdrawal.
It may also be used as part of treatment for alcohol dependence. For some people, it can reduce the rewarding effects of alcohol and help reduce heavy drinking. It does not make alcohol safe and does not treat alcohol withdrawal emergencies.
Its role is supportive rather than curative. Treatment outcomes are influenced by adherence, clinical monitoring, psychological care, and practical support. Patients should discuss realistic goals with their prescriber before beginning therapy.
How naltrexone works
Naltrexone binds to opioid receptors, particularly mu-opioid receptors, without activating them. This prevents opioids from producing their usual effects, such as euphoria and respiratory depression. Attempting to overcome this blockade with larger opioid doses can be dangerous.
In alcohol dependence, opioid receptor blockade is thought to reduce part of the reinforcement associated with drinking. The effect varies between individuals. A patient may notice changes in craving or drinking patterns, but medicine response should be reviewed clinically.
Naltrexone does not cause intoxication when taken as directed. It is also not a sedative or a medicine for immediate craving relief. Consistent use according to the prescribed regimen is important when it is selected for ongoing treatment.
Scientific evidence and treatment expectations
Clinical research supports naltrexone as one possible pharmacological option for alcohol dependence and relapse prevention in opioid dependence. Evidence is strongest when medicine is combined with structured treatment and follow-up. Results differ according to the condition being treated and the person’s circumstances.
Studies generally assess outcomes such as return to opioid use, heavy-drinking days, adherence, and treatment retention. No medicine guarantees abstinence or prevents every relapse. A careful discussion of benefits, limitations, and alternatives is therefore essential.
Clinical guidelines may differ in their preferred treatment pathways. Healthcare professionals consider co-existing illness, medicines already being taken, and the patient’s ability to remain opioid-free before initiation. Do not use research summaries as a substitute for an individual assessment.
Taking naltrexone safely
Take naltrexone exactly as stated on the prescription label and by the prescriber. Do not alter the dose, stop suddenly, or take extra tablets to compensate for a missed dose unless a healthcare professional advises this. Directions can vary depending on the treatment indication and formulation.
Before treatment for opioid dependence, patients must have been free from opioids for a clinically appropriate interval. The required interval depends on the opioid used, including whether it was short-acting or long-acting. A clinician may use assessment methods to reduce the risk of precipitated withdrawal.
If a dose is missed, seek advice from the prescribing service or pharmacy rather than doubling the next dose. Keep follow-up appointments, particularly early in treatment. Report new symptoms, relapse, planned surgery, or any need for pain relief promptly.
Duration of effect and elimination
After an oral dose, naltrexone and its active metabolite remain in the body for a limited period, but receptor blockade can last longer than the medicine’s measurable blood level. The duration depends on dose, metabolism, liver function, and individual factors. A prescriber can explain what this means for a specific regimen.
Oral naltrexone is commonly associated with opioid-blocking effects that may extend for roughly a day or longer after a dose. This is not a reason to take opioids or test the blockade. The response to opioids can become unpredictable and dangerous after treatment is stopped.
The body processes naltrexone mainly through the liver and eliminates metabolites largely through urine. Elimination is not identical for every person. Liver impairment and other medical factors may require closer review or a different treatment approach.
Dependence, addiction, and stopping treatment
Naltrexone is not considered addictive and does not normally cause physical dependence. It does not create the opioid high that it is designed to block. However, stopping treatment can remove opioid blockade and increase vulnerability to relapse.
After a period without opioids, tolerance to opioids is reduced. A previously tolerated opioid dose may then cause life-threatening overdose, especially if a person returns to use after missing or stopping naltrexone. This risk should be discussed clearly before treatment begins.
Do not discontinue naltrexone solely because cravings, mood, or drinking patterns change. Contact the prescriber to review the treatment plan. Ongoing support is particularly important during transitions in care.
Common and serious side effects
Possible side effects include nausea, stomach discomfort, headache, dizziness, tiredness, sleep disturbance, anxiety, and reduced appetite. Many effects are mild or improve as treatment continues. Persistent or troublesome symptoms should be discussed with a pharmacist or prescriber.
Naltrexone can be associated with liver-related concerns, particularly in people with existing liver disease or at unsuitable doses. Symptoms such as yellowing of the skin or eyes, dark urine, marked fatigue, or persistent upper abdominal pain need urgent medical assessment. Liver tests may be considered before and during treatment.
Changes in mood, including low mood or suicidal thoughts, should be taken seriously. Seek urgent help if there is immediate danger or a mental-health crisis. Patients and close contacts should know how to access local emergency and healthcare services in Norway.
Allergy and when not to use it
Do not take naltrexone if there has been a previous serious allergic reaction to naltrexone or a listed ingredient in the supplied product. Signs of a serious allergic reaction can include swelling of the face or throat, breathing difficulty, widespread rash, or faintness. Seek emergency care immediately if these occur.
Naltrexone is generally unsuitable for people currently using opioid medicines or with opioid dependence that has not been fully withdrawn. It may also be unsuitable when opioid pain relief is required. Tell the prescriber about all pain medicines, cough products, and opioid-containing treatments.
Severe liver problems, acute hepatitis, and certain other health conditions require specialist consideration. Pregnancy, breastfeeding, and plans for conception should also be discussed before starting treatment. The patient information leaflet and prescriber’s assessment remain important sources of product-specific guidance.
Age limits and additional restrictions
Naltrexone treatment for children and adolescents requires specialist judgement because authorisation and evidence may be more limited than for adults. Do not give this medicine to a young person unless it has been specifically prescribed for them. The dose and monitoring plan must be individualised.
Older adults may need closer monitoring when they have liver, kidney, neurological, or multiple medication concerns. Age alone does not determine suitability. The full medical picture is more important than a general age category.
People whose work involves driving, machinery, or safety-critical tasks should consider possible dizziness or reduced alertness when starting treatment. Avoid such activities until the personal effect is known. Employers and healthcare professionals can help address work-related safety concerns where appropriate.
Alcohol and medicine interactions
Naltrexone may be prescribed for alcohol dependence, but drinking alcohol while taking it can still cause harm. The medicine does not prevent alcohol intoxication, accidents, liver damage, or alcohol poisoning. Discuss alcohol goals openly with the treating clinician.
The most important interactions involve opioids. These include prescription painkillers, opioid substitution medicines, some cough or diarrhoea products, and illicit opioids. Always inform dentists, surgeons, emergency teams, and pharmacists that naltrexone is being used.
Other medicines and supplements can also affect treatment decisions, particularly those with possible liver effects. Provide a complete list, including non-prescription products and herbal remedies. Never assume that a product is safe simply because it is sold without a prescription.
Overdose and emergency situations
Taking more naltrexone than prescribed may increase the risk of adverse effects and requires medical advice. Contact a poison information service, urgent-care provider, or emergency service for guidance after a suspected overdose. Keep the package available so healthcare professionals can identify the product and strength.
A particularly serious danger arises when someone attempts to override naltrexone’s opioid blockade with high opioid doses. This can lead to fatal overdose, especially as the blocking effect wanes. Emergency symptoms include slow or absent breathing, blue lips, unconsciousness, or inability to wake the person.
Call emergency services immediately for suspected opioid overdose or severe allergic symptoms. Naloxone may be used in opioid overdose by trained responders, but emergency assessment is still essential. Naltrexone is not a substitute for emergency overdose treatment.
Alternatives to naltrexone
Alternatives depend on whether treatment concerns alcohol dependence or opioid dependence. For alcohol dependence, clinicians may consider other approved medicines alongside psychological and social interventions. Suitability depends on medical history, drinking pattern, liver status, and personal goals.
For opioid use disorder, opioid agonist treatments such as buprenorphine or methadone may be appropriate for many patients. These treatments work differently from naltrexone and require separate clinical pathways. Switching between approaches should always be medically supervised.
Non-medicine support remains valuable regardless of the selected treatment. This can include counselling, peer support, family involvement, housing assistance, and mental-health care. A clinician can help compare options without assuming that one route fits everyone.
Storage and handling
Store naltrexone in its original packaging and follow the temperature instructions on the supplied leaflet. Keep it dry and protected from conditions that could damage the tablets or packaging. Do not use medicine that is expired, visibly damaged, or of uncertain origin.
Keep all medicines out of sight and reach of children and other people who could take them accidentally. Do not share naltrexone with anyone else, even if their symptoms appear similar. Prescribed treatment is based on an individual safety assessment.
Ask a pharmacy about safe disposal of unused or expired tablets. Do not keep medicines for future self-treatment. Proper disposal helps reduce accidental exposure and environmental contamination.
Pharmacy access and regulatory checks in Norway
Naltrexone should be obtained through a regulated pharmacy after the required prescription review. Availability, dispensing rules, and reimbursement arrangements can change, so the pharmacy should confirm current requirements before supply. A responsible service will not bypass Norwegian medicine regulations.
Our pharmacy supports secure prescription handling and pharmacist review where this medicine is legally supplied. Patients should provide accurate medical and contact information during the purchase process. If the prescription is missing, expired, or unsuitable, supply may need to be paused until the issue is resolved.
For patients searching for naltrexone online, pharmacy registration, clear contact details, and transparent medicine information are important safety signals. Avoid websites that promise restricted medicines with no clinical checks. Counterfeit or inappropriate medicines can create substantial health risks.
Typical costs and value considerations
The price of naltrexone can vary between pharmacies, pack sizes, manufacturers, and any applicable reimbursement arrangement. Other online pharmacies in Norway may show different illustrative retail prices depending on these factors. A current checkout total is more reliable than an old listing or a general web search.
When comparing costs, check whether the figure includes prescription processing, dispensing, delivery, and any consultation-related charges. A lower advertised amount may not reflect the final payable total. Regulated supply and professional review should remain more important than promotional claims.
Patients who are concerned about affordability can ask the pharmacy or prescriber about authorised generic options and relevant support arrangements. Do not split, share, or ration medicine to reduce costs without professional advice. Inconsistent treatment may increase health and relapse risks.
How to place a pharmacy purchase
Begin by selecting the prescribed naltrexone presentation and entering the requested patient details accurately. Submit the prescription through the pharmacy’s approved process when required. A pharmacist may contact the patient or prescriber if clarification is needed.
Before confirming payment, review the medicine name, strength, quantity, delivery address, and total charge. Read the patient leaflet supplied with the medicine when it arrives. Contact the pharmacy promptly if the delivered product does not match the prescription details.
Purchasing through a regulated pharmacy can offer privacy, prescription verification, and access to professional support. It also helps patients avoid unverified supply chains. Medical questions about suitability, dosing, side effects, or opioid-free intervals should be directed to a qualified healthcare professional.
Delivery updates and package tracking
After dispatch, the pharmacy may provide a shipment confirmation and tracking information where the selected delivery method supports it. Tracking allows the recipient to follow estimated delivery progress and prepare to receive the parcel securely. Delivery times can vary with location, carrier service, and operational conditions.
Use a private email address and ensure that the delivery contact details are correct. If a tracked parcel appears delayed, contact the carrier first where appropriate and then the pharmacy for further assistance. Do not leave medicines in locations exposed to heat, moisture, or unauthorised access.
Inspect the package on arrival and store the medicine according to its leaflet without delay. Report damaged, tampered, or incorrect deliveries to the pharmacy before using the product. For urgent treatment needs, do not rely on delivery alone; contact a local healthcare service or pharmacy for timely advice.
Frequently Asked Questions
How is naltrexone different from naloxone?
Although their names are similar, they have different roles. Naltrexone is an opioid receptor blocker used as part of longer-term treatment plans, while naloxone is used urgently to reverse an opioid overdose. Naltrexone is not a substitute for emergency overdose care.
Is low-dose naltrexone the same as standard naltrexone treatment?
Low-dose naltrexone (LDN) refers to doses lower than those commonly used for alcohol or opioid dependence. It is sometimes discussed for other conditions, but its use, evidence base, and regulatory status can differ from approved naltrexone treatment. A clinician should assess whether it is appropriate for the individual indication.
Can naltrexone be used for weight loss?
Naltrexone alone is not generally approved as a weight-loss medicine. In some settings, it is combined with another active ingredient in a specific prescription treatment for weight management. Suitability depends on medical history, current medicines, and the authorised product available in Norway.
Will naltrexone treat alcohol withdrawal symptoms?
Naltrexone is not intended to manage acute alcohol withdrawal, which can occasionally become medically serious. Symptoms such as seizures, confusion, hallucinations, or severe shaking require urgent medical assessment. It may be considered later within a broader treatment plan when a clinician considers it suitable.
Do opioid-containing cough or diarrhoea medicines still work with naltrexone?
Naltrexone can reduce or block the effects of medicines containing opioids, including some products used for cough, pain, or diarrhoea. Do not attempt to overcome this effect by taking more medicine, as this can be dangerous. Check the active ingredients with a pharmacist before using any new non-prescription product.
What should I tell my dentist or surgical team if I take naltrexone?
Tell the dentist, anaesthetist, surgeon, and pharmacist that you use naltrexone well before a planned procedure. This information helps the team plan pain relief appropriately because some standard opioid pain medicines may be less effective. For unexpected urgent care, disclose naltrexone use as soon as possible.
Can naltrexone affect a workplace or sports drug test?
Naltrexone is not an opioid and is not ordinarily expected to produce an opioid-positive result. However, testing methods and reporting requirements vary, so it is sensible to declare prescribed medicines to the testing provider in advance. Keep documentation from the prescriber or dispensing pharmacy if this is relevant.
Can naltrexone be used during pregnancy or while breastfeeding?
Pregnancy and breastfeeding require an individual benefit-risk assessment because information may be limited and treatment needs vary. Do not start, stop, or change naltrexone on your own during this time. A prescriber or maternity-care professional in Norway can advise based on the specific circumstances.
Does naltrexone contain an opioid or cause an opioid high?
No. Naltrexone is not an opioid and does not create an opioid high. Instead, it attaches to opioid receptors and blocks or reduces the effects of opioid medicines and illicit opioids.
Is counselling still useful when naltrexone is part of treatment?
Yes. Naltrexone is often used alongside counselling, peer support, and practical relapse-prevention strategies rather than as a stand-alone solution. The most suitable support can differ according to the person’s goals, health needs, and access to local services.
Pharmacist Review
This Naltrexone product page has been professionally reviewed for clarity, balanced medicine information and relevance to pharmacy practice in Norway.
| Review detail | Information |
|---|---|
| Reviewed by | Ingrid Solberg, Master of Pharmacy (Cand.pharm.) |
| Professional identifier | HPR no. 7852146 |
| Professional reference | Norwegian Directorate of Health |
| Review date | 24 March 2025 |
The content addresses appropriate use, important precautions, adverse effects and interaction considerations for naltrexone. Treatment should be individually assessed, particularly where opioid use, liver disease or other medicines may affect suitability.
Medical disclaimer: This material is provided for informational purposes only and does not replace consultation with a doctor. Seek medical advice before starting, changing or stopping treatment.
Pharmacy Location and Opening Hours
For Naltrexone, visit our pharmacy at Stenersgata 1, 0050 Oslo, Norway.
| Days | Opening hours |
|---|---|
| Monday–Friday | 10:00–21:00 |
| Saturday | 10:00–19:00 |