No. Naltrexone will displace methadone from opioid receptors, causing sudden and severe withdrawal. A complete wash-out from methadone (typically 7-10 days) is required before initiating Naltrexone.
Yes. Naltrexone is only started after an alcohol-detoxification period, usually 3-7 days of abstinence, to avoid precipitating withdrawal-like symptoms and to allow baseline liver tests.
Many patients notice a reduction in cravings within the first two weeks, but optimal benefit may take 4-6 weeks of consistent daily dosing.
Both contain the same active ingredient (50 mg Naltrexone) and must meet the same quality standards set by the MHRA. Inactive ingredients may vary slightly, which can affect tolerability in some individuals.
Generally, ibuprofen does not interact with Naltrexone. However, avoid any opioid-containing pain medicines (e.g., codeine) while on Naltrexone.
Contact your prescriber for guidance. In many cases, the medication can be restarted at the regular dose after a short gap, but a professional assessment is advisable to ensure safety.
No specific diet is required, but heavy alcohol consumption should be avoided. Taking the tablet with a light snack may lessen nausea.
When used off-label for smoking, clinicians typically assess nicotine cravings, monitor liver enzymes, and combine the drug with standard nicotine-replacement therapy and behavioural support.
Weight changes are not a common side effect. Any significant change in appetite or weight should be discussed with a healthcare professional.
Naltrexone is not a prohibited substance in standard occupational drug-testing programs or by the World Anti-Doping Agency (WADA). However, athletes should disclose use to their governing bodies if required.
Naltrexone is a prescription-only medicine (POM) used in the United Kingdom to help people stop using opioids and to reduce harmful drinking. It belongs to the therapeutic class of addiction-treatment agents and is available as a 50 mg oral pill. Various pharmaceutical companies manufacture Naltrexone tablets; the active ingredient is the same across brands.
Naltrexone is an opioid receptor antagonist. It binds tightly to mu, kappa, and delta opioid receptors in the brain and spinal cord without activating them. By occupying these receptors, Naltrexone blocks the effects of any opioid that might be taken, preventing the euphoria and respiratory depression that opioids normally produce.
In alcohol dependence, the drug’s action on the endogenous opioid system is thought to reduce the rewarding feelings associated with drinking, thereby decreasing cravings and the likelihood of relapse.
Key pharmacologic points
Small clinical trials have explored Naltrexone as an adjunct to nicotine replacement therapy or behavioural counselling for quitting smoking. Results suggest a modest reduction in cigarette cravings, but the evidence is insufficient for routine recommendation.
Disclaimer: Use of Naltrexone for smoking cessation is not approved by the Medicines and Healthcare products Regulatory Agency (MHRA). Off-label application should be supervised by a qualified healthcare professional who can assess individual risk-benefit considerations.
These effects are usually mild and may improve with continued therapy.
Standard dosing: One 50 mg tablet taken orally once daily, preferably at the same time each day.
Special populations:
Hepatic impairment: Consider a lower dose (e.g., 25 mg) or extended interval; monitor liver enzymes every 2-4 weeks.
Renal impairment: No dosage change required, but follow clinical judgment.
Administration tips: Swallow the tablet whole with water; do not crush or chew.
Missed dose: Take the missed tablet as soon as remembered unless it is close to the time of the next scheduled dose-do not double-dose.
Overdose: Symptoms may include severe nausea, vomiting, dizziness, and abdominal pain. Seek emergency care; supportive care is the mainstay of treatment. No specific antidote is required.
Discontinuation: Naltrexone does not cause physical dependence; it can be stopped without tapering. However, a gradual reduction may be considered if cravings increase sharply.
This article provides educational information about Naltrexone and is not a substitute for professional medical advice. Treatment decisions, including use for unapproved indications, must be made under the guidance of a qualified healthcare provider. The content is intended for informational purposes and does not constitute medical recommendations. Always consult a physician before starting, stopping, or changing any medication regimen.
