NALTREXONE 50MG TABLETS 28`S

Naltrexone is a potent, long-acting, competitive opioid receptor antagonist — it blocks mu-, kappa-, and delta-opioid receptors, preventing opioids and endogenous opioid peptides (endorphins, enkephalins) from exerting their effects. In addiction medicine, blocking the rewarding and reinforcing effects of opioids and alcohol removes the positive reinforcement that drives addiction.

It is used for:

•       Opioid use disorder (OUD) — prevention of relapse to opioid dependence after detoxification (opioid-free period). Naltrexone blocks the euphoric effects of opioids, removing the incentive to use.

•       Alcohol use disorder (AUD) — reduces alcohol craving and the reinforcing effects of alcohol. Shown in RCTs to reduce heavy drinking days and total alcohol consumption.

It is also used off-label at very low doses (LDN — 1–4.5 mg/day) for various inflammatory, immune, and pain conditions, but this is investigational and not within the licensed indication of this 50 mg tablet.

Standard dose: 50 mg once daily. Take with food to reduce nausea. Swallow whole with water. Alternatively, 100 mg may be prescribed every other day, or 150 mg three times weekly, for supervised dosing programmes.

Naltrexone is contraindicated in: patients currently using opioids or in acute opioid withdrawal; patients who have failed the naloxone challenge test; patients with acute hepatitis or liver failure; known hypersensitivity; and patients requiring opioid analgesia (opioid pain medicines will be ineffective).

Use with caution in: hepatic impairment (hepatotoxic at high doses — monitor LFTs); renal impairment; depression (psychological support essential alongside pharmacotherapy); and pregnancy/breastfeeding.

•       All opioid medications (morphine, codeine, tramadol, oxycodone, methadone, fentanyl, buprenorphine): completely blocked by naltrexone — no analgesic, sedative, or euphoric effect. Non-opioid analgesia (NSAIDs, paracetamol, regional anaesthesia) must be used for pain management.

•       Thioridazine: additive lethargy and somnolence — avoid.

•       Yohimbine: may cause rapid heart rate in combination — avoid.

Store below 25°C. Original packaging. Keep out of reach of children.

Naltrexone is an important pharmacological tool in recovery from opioid or alcohol dependence. It blocks the 'reward' of using — removing the high or buzz that drives the cycle of addiction. It works best as part of a comprehensive recovery programme that includes psychological therapy, social support, and relapse prevention counselling.

Carry your naltrexone treatment card at all times. If you need pain treatment (for surgery, injury, or medical procedures), tell every healthcare provider you are on naltrexone — opioid pain medicines will not work effectively. Regional anaesthesia, paracetamol, ketamine, or other non-opioid analgesics will need to be used instead.

After stopping naltrexone, your tolerance to opioids is greatly reduced. If you or your loved one relapses to opioid use after stopping naltrexone, a much smaller amount of opioid than before can cause a fatal overdose. Keep naloxone (Narcan) nasal spray or auto-injector at home and make sure a family member knows how to use it.

Naltrexone 50 mg/day is the standard licensed dose for both OUD and AUD. The hepatotoxicity risk is dose-related — first described at investigational doses of 300 mg/day; at 50 mg/day the risk is low but warrants monitoring. LFTs at baseline, monthly for first 3 months, then every 3 months.

The 28-tablet pack covers one month of daily 50 mg dosing. Supervised consumption dosing: some programmes use 100 mg on Monday, 100 mg on Wednesday, 150 mg on Friday — total 350 mg/week, dispensed 3x weekly; confirm which schedule is prescribed. Injectable extended-release naltrexone (Vivitrol — 380 mg IM monthly) is available for patients with poor oral adherence.

The Sinclair Method (naltrexone 50 mg taken 1 hour before each drinking occasion rather than daily) is used for AUD in some centres — this is off-label dosing.

What if I stop naltrexone and then use opioids?

This is life-threatening. Naltrexone reduces your tolerance to opioids. If you stop naltrexone and use opioids at a dose you previously tolerated, you could die of overdose because your body is now much more sensitive. This risk is highest in the first month after stopping. Please have naloxone (Narcan) at home as a safety net.

Will naltrexone stop me from wanting to drink or use drugs?

Naltrexone reduces the craving and the reinforcing 'reward' effect of alcohol and opioids — but it does not completely eliminate cravings. It works best combined with psychological therapy and strong support networks.

I need surgery — what should I tell the anaesthetist?

Tell every healthcare provider: 'I am on naltrexone — opioid pain medicines will not work.' Your anaesthetist will plan non-opioid pain control. In extreme emergencies, very high doses of opioids can partially overcome the block — this must only be managed by experienced anaesthetic staff in monitored settings.

How long do I need to stay on naltrexone?

For OUD: typically at least 6–12 months; some patients benefit from longer-term use. For AUD: duration is variable, guided by your response and clinical judgement. Discuss with your addiction medicine specialist.

Does naltrexone cause withdrawal symptoms?

Naltrexone itself does not cause dependence or withdrawal. However, starting it while any opioids are still in your system will precipitate immediate, severe opioid withdrawal — which is why you must be completely opioid-free before the first dose.