Naltrexone
Naltrexone is an opioid antagonist used for alcohol and opioid dependence; PockDose lists Revia 50mg tablets and Contrave 8/90mg tablets with bupropion.
What naltrexone is for
Naltrexone is used in two situations: to help people dependent on opioids stop, and to cut cravings in people dependent on alcohol. As an opioid antagonist it sits on opioid receptors and blocks them, which removes much of the reward from alcohol and opioid drugs. It supports counselling and a wider treatment plan rather than replacing them.
How it works
The medicine attaches to opioid receptors in the brain and does not switch them on. Opioid painkillers, heroin and similar drugs then have nowhere to attach, so their usual effect is blocked. The body's own pain-relieving chemicals, called endorphins, are blocked too. With alcohol, the same receptor block reduces the pleasant, rewarding part of drinking, which is thought to be why cravings fall. The effect is not a sudden dislike of alcohol; it is a slow reduction in the urge to drink.
Taking naltrexone
Revia is naltrexone on its own, as 50mg tablets. The usual adult dose is one 50mg tablet once a day; a regular daily slot makes it easier to remember. For opioid dependence, it is started only after you have been free of opioids for 7 to 10 days; taking it while opioids are still in the body can cause sudden withdrawal — feeling ill as the opioid leaves the body. For alcohol dependence, treatment often continues for several months.
Side effects and liver signs
Most side effects are mild: nausea, headache, tiredness, dizziness, trouble sleeping, anxiety and stomach pain. Many ease after the first week or two, and since drowsiness is possible it is worth seeing how the tablet affects you before driving. The serious risk is to the liver. Yellow skin or eyes, dark urine, pain in the upper abdomen or tiredness that does not lift need urgent attention. Naltrexone is not started when the liver is inflamed or failing.
Opioid interactions and the listings
Opioid painkillers such as codeine, morphine, tramadol and fentanyl, and cough medicines that contain an opioid, will not work as expected while naltrexone is active. Contrave is a combination tablet of naltrexone 8mg with bupropion 90mg. It is used for weight management and also sits in the addiction and smoking group with Revia, as well as in weight loss. The naltrexone dose in Contrave is lower than in Revia, and the tablet is taken daily while the dose is raised over the first few weeks. Keep tablets in their original pack, away from heat and damp.
Sources
- Naltrexone: MedlinePlus Drug Information — National Library of Medicine
- Medications to Treat Opioid Use Disorder | National Institute on Drug Abuse (NIDA) — National Institute on Drug Abuse
Where can I buy Naltrexone in Hong Kong?
Naltrexone can be ordered online from PockDose with delivery to Hong Kong. The page lists generic Revia, also sold as Naltrexone tablets, at 50mg, plus the combination tablets generic Contrave, also sold as Bupropion + Naltrexone, at 8/90mg. An order can be cancelled within 24 hours if it has not been dispatched, and support answers 24/7 in English and Cantonese.
What is the price of Naltrexone?
Each of the two naltrexone products has its own price per pack, shown on its page in HKD or your selected currency; larger packs usually cost less per unit.
Do I need a prescription to order Naltrexone?
PockDose does not ask you to upload a prescription when you order naltrexone. See the ordering FAQ for details.
What is another name for naltrexone?
Revia is a brand name of naltrexone, which is also sold as Depade, Naltima, Nodict and Vivitrol. Here, naltrexone can be bought online as generic Revia. These are generics, not the original brand.
Can I drink alcohol while taking naltrexone?
Yes, naltrexone does not react with alcohol the way disulfiram does. It works by reducing the rewarding pull of a drink, not by making you ill if you have one. Some people still notice more dizziness or drowsiness when they drink on it, so it is worth knowing how it affects you.
Is Contrave the same as naltrexone?
Contrave contains naltrexone, but it also contains bupropion, and the naltrexone dose is much lower than in a Revia 50mg tablet. Contrave is used for weight management, while Revia is used for alcohol dependence and opioid dependence.
What happens if you take naltrexone with opioid painkillers?
Opioid painkillers and opioid cough medicines will not give their usual effect while naltrexone is in the body, because the medicine blocks the receptors they need. If opioids are still in your system when you start naltrexone, it can also trigger withdrawal.
How long do you take naltrexone for?
Weeks to months, depending on why it is taken. For alcohol dependence a course of several months is usual. In opioid dependence it runs as part of a longer plan with counselling or support, and ending it early is when cravings tend to return.
Can naltrexone be used for weight loss on its own?
Naltrexone by itself is not a weight-loss medicine. The combination product Contrave pairs a lower dose of naltrexone with bupropion and is used for weight management alongside changes to diet and activity.