Naltrexone overview
Naltrexone is a medicine that blocks the effects of opioid medicines and other opioids. It is used as part of a structured treatment plan, rather than as a stand-alone solution. In the Netherlands, appropriate assessment and follow-up by a qualified prescriber are important for safe use.
This medicine is not an opioid and does not produce opioid-type pain relief or euphoria. Instead, it occupies opioid receptors and can reduce the reinforcing effects of opioids. Its role depends on the diagnosis, treatment goals, and the patient’s medical history.
Naltrexone treatment commonly includes medical monitoring, counselling, and practical support for recovery. The medicine may be prescribed in specialist addiction care or other appropriate clinical settings. A pharmacist can help explain dispensing instructions and safe medicine handling.
What Naltrexone is used for
Naltrexone is principally used to support relapse prevention after opioid dependence when a person is no longer physically dependent on opioids. It may also be used in alcohol-use treatment to help reduce the rewarding effects of alcohol and support a person’s agreed treatment goals. The precise indication and treatment approach should be determined by a clinician.
It does not treat acute opioid withdrawal and can trigger severe withdrawal if opioids are still present in the body. For this reason, clinicians normally confirm an adequate opioid-free period before treatment begins. The required interval varies according to the opioid used, dose, formulation, and individual circumstances.
Naltrexone is not intended to replace emergency care for intoxication, overdose, or withdrawal. People seeking help for substance use can contact their GP, addiction-care service, or emergency services when urgent support is needed. Recovery plans are often more effective when they address physical health, mental health, housing, and social support.
Active ingredient and medicine forms
The active ingredient is naltrexone hydrochloride, usually described simply as naltrexone. It is an opioid receptor antagonist, meaning it blocks rather than activates opioid receptors. Product information should always be checked because strengths, excipients, and authorised presentations can differ.
Oral tablets are the most familiar formulation in many settings, often supplied in a standard daily strength determined by the prescriber. Long-acting injectable formulations exist in some countries, although availability and authorisation may differ in the Netherlands. A pharmacy should dispense only the formulation written on a valid prescription.
Do not split, crush, or change a tablet regimen unless a pharmacist or prescriber confirms that this is suitable. The outer carton and patient leaflet identify the strength, batch details, expiry date, and storage directions. Ask the dispensing pharmacist if the product appearance differs from a previous supply.
Origin and development of Naltrexone
Naltrexone was developed from earlier opioid-antagonist research aimed at understanding and blocking opioid receptor activity. Its creation followed work on compounds structurally related to opioids but designed to prevent opioid effects. This scientific pathway led to a medicine used in carefully selected addiction-treatment programmes.
Clinical use developed alongside improved understanding of relapse prevention and the importance of psychosocial care. Naltrexone has therefore generally been studied as one element of a broader treatment approach. It is not a universal treatment for every form of substance dependence.
Modern prescribing decisions rely on current product information, clinical guidance, and individual risk assessment. Earlier history does not replace the need for present-day safety checks. This is particularly relevant when there has been recent opioid exposure or impaired liver function.
How Naltrexone works
Naltrexone binds strongly to opioid receptors, especially mu-opioid receptors, without activating them. When opioids are taken, their expected effects may therefore be reduced or blocked. This mechanism can help support abstinence-based treatment when used under clinical supervision.
In alcohol-use treatment, the mechanism is more complex and relates partly to opioid pathways involved in reward. Some people may experience less reinforcement from alcohol while taking naltrexone. Response varies, and the medicine does not remove the health risks of drinking alcohol.
Because opioid blockade can be overcome unpredictably by taking larger opioid doses, attempts to do so are dangerous. Serious poisoning, breathing problems, and death can occur, especially after naltrexone is stopped and opioid tolerance has fallen. Patients should discuss pain management and emergency plans with their clinical team.
Taking Naltrexone safely
Take Naltrexone exactly as prescribed and follow the instructions on the pharmacy label. It may generally be taken with or without food, although taking it with food may help if nausea occurs. Never start treatment after recent opioid use without clinical confirmation that it is safe.
Before the first dose, tell the prescriber about all prescription medicines, non-prescription medicines, supplements, and recent opioid exposure. Opioids can be present in pain medicines, cough products, diarrhoea treatments, and illicit substances. A clinician may use history, examination, testing, or a supervised challenge where appropriate.
If a dose is missed, patients should follow the advice in the patient leaflet or ask their pharmacist rather than doubling the next dose. Do not stop, restart, or alter treatment independently. Consistent follow-up allows benefits, adverse effects, and treatment goals to be reviewed.
How long the effects and presence in the body last
The opioid-blocking effect of an oral Naltrexone dose can extend beyond the time the medicine is measurable at high levels in blood. The duration depends on dose, formulation, liver function, metabolism, and the opioid concerned. A prescriber can explain the expected coverage for an individual treatment plan.
Naltrexone itself is processed in the body and converted into active metabolites. Elimination is not identical for every person, so a single universal “clearance time” is not reliable. Laboratory detection windows also depend on the test method and should not be inferred from dosing information alone.
Even after treatment is discontinued, reduced opioid tolerance may create an overdose risk if opioids are resumed. This risk can be especially high after a period of abstinence. Anyone considering stopping Naltrexone should discuss overdose prevention and emergency support with their healthcare professional.
Research and clinical evidence
Scientific research supports Naltrexone as an option for selected people with alcohol-use disorder or opioid-use disorder. Evidence is strongest when the medicine is combined with ongoing clinical contact and behavioural or psychosocial support. Outcomes differ according to adherence, patient selection, co-existing conditions, and treatment setting.
Research does not show that one medicine is right for every person. For opioid-use disorder, other evidence-based medicines may be more suitable depending on treatment goals and readiness for different approaches. Shared decision-making is important because benefits and risks are individual.
Healthcare professionals use current national guidance, approved product information, and clinical judgement when considering Naltrexone. A reputable pharmacy does not claim guaranteed outcomes or promote it as a quick cure. Treatment should be reviewed if symptoms, cravings, adverse effects, or circumstances change.
Dependence and addiction potential
Naltrexone is not generally considered addictive and does not create opioid dependence. It does not cause the opioid-like intoxication that drives misuse of opioid medicines. However, this does not mean it is suitable for unsupervised use.
Physical dependence on opioids must be addressed before Naltrexone is started. Taking it while opioids remain active can cause abrupt, intense withdrawal symptoms. This reaction may require urgent medical assessment depending on its severity.
Psychological and social support remain important even though Naltrexone itself has low misuse potential. Cravings, relapse risk, anxiety, and low mood may still need active care. Patients should seek professional help promptly if they feel at risk of returning to opioid use.
Side effects and allergic reactions
Possible side effects include nausea, abdominal discomfort, headache, dizziness, tiredness, sleep changes, and reduced appetite. Not everyone experiences these effects, and some may improve as the body adjusts. Persistent or troublesome symptoms should be discussed with a prescriber or pharmacist.
Rare but potentially serious concerns include signs of liver problems, such as yellowing of the skin or eyes, dark urine, marked fatigue, or persistent upper abdominal pain. Seek timely medical advice if these symptoms occur. Liver tests may be considered before and during treatment when clinically appropriate.
Allergic reactions are uncommon but require urgent attention if there is swelling of the face, lips, tongue, or throat, breathing difficulty, widespread rash, or faintness. Stop taking the medicine and seek emergency care if a severe allergic reaction is suspected. Tell future healthcare providers about any confirmed medicine allergy.
Who should not take Naltrexone
Naltrexone is generally unsuitable for people currently using opioids, receiving opioid substitution treatment, or experiencing opioid withdrawal. It is also not appropriate for people who need opioid pain relief unless a specialist has planned their care. Starting treatment in these situations can create serious risks.
People with known hypersensitivity to naltrexone or any listed ingredient should not use the product. Significant liver disease, acute hepatitis, or abnormal liver function may require avoidance or specialist evaluation. The prescriber will consider the balance of potential benefit and harm.
Pregnancy, breastfeeding, kidney impairment, mental-health conditions, and a history of self-harm should be discussed before treatment. This does not automatically rule out use, but it may affect the care plan and monitoring. Never conceal substance use or medication use from the treating clinician.
Age limits and additional restrictions
Naltrexone use in children and adolescents requires specialist judgement because product authorisations and evidence may vary by age group and indication. It should not be assumed suitable for anyone under 18 years of age. Parents and carers should obtain advice from an appropriate paediatric or addiction-care specialist.
Adults should also be assessed individually, particularly if they are older, frail, or have multiple medical conditions. The medicine may interact with clinical needs that are not obvious from a simple symptom description. A full medication review improves safety.
Driving or using machinery may be affected if Naltrexone causes dizziness, fatigue, or reduced concentration. Patients should assess their response before undertaking safety-sensitive activities. Dutch workplace and road-safety obligations continue to apply while taking any medicine that affects alertness.
Alcohol, opioids, and medicine interactions
Naltrexone is sometimes prescribed for alcohol-use treatment, but it does not make alcohol safe to consume. Alcohol can worsen liver strain, impair judgement, and increase the likelihood of missed doses or relapse. Discuss alcohol goals openly with the prescriber managing treatment.
The most important interaction concern is with opioids, including some prescription painkillers and medicines used during surgery or emergency care. Tell dentists, doctors, pharmacists, and emergency staff that you take Naltrexone. A medical alert card or documented treatment information can be helpful.
Other medicines may also require review, especially those that affect the liver or cause dizziness. Do not rely on internet interaction checkers as a replacement for professional advice. Ask a pharmacist before adding any new medicine, herbal product, or recreational substance.
Overdose and emergency action
Taking more Naltrexone than prescribed may increase adverse effects and requires prompt professional advice. Contact a doctor, pharmacist, poison-information service, or emergency service according to the symptoms and local advice. Keep the medicine packaging available so healthcare professionals can identify the product and strength.
A particularly dangerous scenario is trying to overcome opioid blockade by taking high doses of opioids. Once Naltrexone’s blocking effect diminishes, delayed opioid toxicity and life-threatening breathing suppression can occur. Call 112 in the Netherlands immediately if someone is unconscious, has slow or absent breathing, blue lips, or cannot be awakened.
Do not leave a person with suspected overdose alone while waiting for emergency help. If naloxone is available and opioid overdose is suspected, use it according to its instructions while emergency assistance is arranged. Emergency care is still essential because naloxone may wear off before the opioid does.
Alternatives to Naltrexone
Alternatives depend on whether treatment is for alcohol-use disorder, opioid-use disorder, or another clinician-determined indication. For opioid-use disorder, options may include opioid agonist or partial-agonist treatments delivered through specialist care. These medicines have different benefits, restrictions, and monitoring needs.
For alcohol-use disorder, clinicians may consider other approved medicines alongside psychological interventions and community support. Suitability depends on liver health, kidney function, drinking pattern, other medicines, and personal treatment goals. No alternative should be started or substituted without a prescribing assessment.
Non-medicine approaches remain important for many people. Motivational support, cognitive behavioural approaches, peer support, and structured addiction-care programmes can complement pharmacological treatment. A clinician can help identify services available locally in the Netherlands.
Naltrexone prescription status in the Netherlands
Naltrexone is a medicine that should be supplied only following appropriate medical assessment and a valid prescription where required by Dutch rules. Claims that it is available with no prescription should be treated cautiously and verified with a registered pharmacy. A legitimate pharmacy will not bypass safeguards designed to prevent precipitated withdrawal and unsafe interactions.
Our pharmacy’s online service is designed to support lawful dispensing, not to replace a prescriber’s evaluation. Patients may need to provide a valid prescription or complete the clinical steps required under applicable regulations. Availability can depend on the specific product, strength, stock status, and national requirements.
Using an unverified seller creates risks of counterfeit, incorrectly stored, or unsuitable medicines. Check that the pharmacy displays clear contact details, professional registration information, privacy practices, and dispensing procedures. When in doubt, consult a Dutch pharmacist or healthcare professional before payment.
Price considerations at Dutch online pharmacies
Naltrexone price can vary between pharmacies because of product presentation, manufacturer, dispensing fees, delivery arrangements, and reimbursement status. Any amount displayed online should be treated as current only at the time of viewing. Patients should review the total checkout cost rather than comparing a medicine price alone.
Other online pharmacies in the Netherlands may show different prices for equivalent prescribed strengths or pack sizes. The lowest advertised amount is not always the best value if professional checks, secure delivery, or supply-chain assurance are unclear. Reimbursement and personal contributions may also depend on the insurer and indication.
Our pharmacy provides transparent product and service information before confirmation where applicable. Contact the pharmacy team if you need clarification about pack size, a prescription requirement, or delivery charges. Do not choose an alternative strength simply because it appears less expensive.
Benefits of a regulated online pharmacy service
A regulated online pharmacy can make repeat dispensing more convenient for patients with an existing prescription and treatment plan. It can offer secure access to medicine information, pharmacist support, and home delivery options where permitted. Convenience should never replace urgent medical evaluation or regular clinical follow-up.
Patients can review product details before requesting supply and can ask questions about storage, missed doses, or administration. Discreet delivery may be helpful for people balancing treatment with work or family commitments. Personal health information should be handled through secure systems and in line with applicable privacy requirements.
To buy Naltrexone responsibly, use a pharmacy that checks eligibility and follows Dutch dispensing standards. Avoid websites that promise unrestricted access, guaranteed results, or unsafe shortcuts. Responsible supply supports continuity of care and reduces avoidable medicine risks.
How to request Naltrexone from our pharmacy
Begin by selecting the prescribed Naltrexone product and reviewing the listed strength and pack information. Submit the prescription or follow the clinical verification process requested by the pharmacy. The pharmacy team may contact you if any detail needs clarification before dispensing.
Before confirming a request, review the delivery address, contact information, costs, and any patient information provided. Keep your prescriber informed if your treatment has changed, including recent opioid use or new medicines. Do not use a previous prescription for a changed clinical situation without checking whether it remains appropriate.
Once dispensing is approved, the medicine is prepared and packaged for secure delivery in accordance with pharmacy procedures. Keep the confirmation and product information for your records. Contact the pharmacy promptly if the received medicine, strength, or quantity does not match the authorised supply.
Delivery tracking and receiving your medicine
After a purchase has been processed and dispatched, tracking information may be provided when the selected delivery service supports it. Tracking helps recipients follow parcel progress and arrange receipt where necessary. Delivery times can vary with stock availability, prescription checks, destination, and carrier operations.
Inspect the outer package when it arrives and confirm that the name, strength, and expiry date are correct before use. Do not use tablets if the packaging appears damaged, tampered with, or exposed to conditions that may have affected quality. Contact the pharmacy before taking a product that raises any concern.
Keep Naltrexone out of sight and reach of children and anyone for whom it was not prescribed. Never share it with another person, even if their symptoms seem similar. Unused or expired medicine should be returned to a pharmacy for safe disposal rather than thrown into household waste or flushed away.
Storage and follow-up during treatment
Store Naltrexone in its original packaging at the temperature and conditions stated on the carton and leaflet. Protect it from moisture and excessive heat, and do not keep it in a bathroom or car. The expiry date applies only when the medicine has been stored correctly.
Regular follow-up allows the treatment team to review adherence, cravings, alcohol or opioid exposure, side effects, mood, and liver-related concerns. Be honest about difficulties, including missed doses or a lapse in substance use. Early discussion usually gives the care team more options to help safely.
Naltrexone can be a valuable part of medically supervised recovery care, but it requires informed use and reliable support. For individual advice, speak with the prescriber or pharmacist who knows your health history. Seek urgent care for severe withdrawal, suspected overdose, serious allergic symptoms, or breathing problems.
Frequently Asked Questions
Are liver blood tests usually needed with Naltrexone?
A clinician may review liver function before treatment and repeat testing when clinically appropriate, particularly if there is a history of liver disease or symptoms such as yellowing of the skin or eyes, dark urine, or persistent upper-abdominal discomfort. The appropriate monitoring schedule is individual and should be determined by the prescriber.
Can Naltrexone affect a workplace drug test?
Naltrexone is not an opioid and is not normally included in standard workplace drug panels. It is not generally expected to produce a positive opioid result, but testing methods vary; disclose prescribed medicines to the testing provider if required.
What is the difference between Naltrexone and naloxone?
Both medicines act on opioid receptors, but their usual roles differ. Naloxone is used for the urgent reversal of an opioid overdose, whereas Naltrexone is used as part of ongoing treatment plans for alcohol or opioid dependence after clinical assessment.
Can Naltrexone be used during pregnancy or while breastfeeding?
Pregnancy and breastfeeding require an individual assessment of potential benefits, risks, and available treatment options. Anyone who is pregnant, planning pregnancy, or breastfeeding should discuss Naltrexone with the clinician managing their care before starting, stopping, or changing treatment.
Does Naltrexone affect fertility or hormonal contraception?
There is no established evidence that Naltrexone reduces the effectiveness of hormonal contraception or directly impairs fertility. However, individual medical circumstances and concurrent medicines matter, so questions about conception or contraception should be reviewed with a healthcare professional.
Should I tell a dentist or hospital clinician that I take Naltrexone?
Yes. Tell all healthcare professionals, including dentists and emergency teams, because Naltrexone can affect how opioid-containing pain relief works. Carrying an up-to-date medicine list can help clinicians plan appropriate care if urgent treatment is needed.
Is low-dose Naltrexone the same as standard Naltrexone treatment?
Low-dose Naltrexone refers to doses that differ substantially from established regimens for alcohol or opioid dependence. Its use for other conditions may be off-label, with evidence and regulatory status varying by indication; it should not be substituted for prescribed treatment without clinical guidance.
Can Naltrexone cause weight loss or weight gain?
Weight change is not a reliable expected outcome of Naltrexone treatment. Appetite, alcohol intake, recovery, activity, and other health conditions can all influence weight, so notable or unintended changes should be discussed with a clinician.
Does Naltrexone interfere with routine vaccinations?
Naltrexone is not generally known to reduce the effectiveness of routine vaccines. Inform the vaccinating professional about all medicines and seek medical advice if you have a history of serious vaccine reactions or an acute illness.
What should I do if I develop new low mood or unusual changes in behaviour while taking Naltrexone?
Contact the prescriber promptly if you notice persistent low mood, marked anxiety, agitation, or concerning behavioural changes. Seek urgent help immediately if there are thoughts of self-harm or an immediate risk to safety.
Can I travel within the Netherlands with Naltrexone?
For travel within the Netherlands, keep Naltrexone in its original labelled packaging and carry enough for the planned period. If travelling abroad, check the destination’s medicine rules and carry relevant prescription documentation where appropriate, as requirements can differ between countries.
Pharmacist Review
This Naltrexone product page has been professionally reviewed for clinical accuracy, safe-use information and relevance to patients in the Netherlands.
| Review detail | Information |
|---|---|
| Reviewed by | Marit van Dijk, Registered pharmacist (apotheker) |
| Professional registration | 19064827301 |
| Professional register | BIG Register (CIBG), Netherlands |
| Review date | 8 March 2025 |
The review considers essential information on Naltrexone, including appropriate use, key precautions, interactions and the importance of avoiding opioid use before and during treatment unless specifically directed by the prescribing clinician.
Medical disclaimer: This material is provided for informational purposes only and does not replace advice, diagnosis or consultation with a doctor. Always follow the instructions of your prescriber and pharmacist.
Pharmacy Location and Opening Hours
For Naltrexone, visit our pharmacy at De Lairessestraat 130, 1075 HL Amsterdam, Noord-Holland, Netherlands.
| Days | Opening hours |
|---|---|
| Monday–Friday | 08:30–17:30 |
