Naltrexone Medications

Naltrexone is an opioid antagonist medication used to treat alcohol dependence and opioid addiction by blocking the effects of these substances on the brain.

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Naltrexone

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About Naltrexone

Naltrexone is an opioid-receptor antagonist approved for treating alcohol-dependence and preventing relapse to opioid use after detoxification. Belonging to the class of competitive antagonists at µ-opioid receptors, it blocks the euphoric effects of alcohol and opioid substances without producing sedation. The drug is marketed worldwide under brand names such as ReVia and Depade, and generic tablets are widely available through our online pharmacy. While its primary indication is substance-use disorder, clinicians have explored low-dose formulations for autoimmune conditions and chronic pain, reflecting a growing body of off-label research. Understanding how naltrexone works, its clinical benefits, and safety considerations helps patients make informed choices when they choose to buy naltrexone online.

What is Naltrexone?

Naltrexone belongs to the pharmacological class of opioid-receptor antagonists. The Health Sciences Authority of Singapore approved the product for use in 2005, following earlier clearance by the U.S. Food and Drug Administration (FDA) in 1984 for opioid-dependence and a 1995 FDA extension to treat alcohol-dependence. The molecule binds competitively to µ-opioid receptors in the central nervous system, preventing endogenous and exogenous opioids from activating these sites. By occupying the receptor without triggering a response, naltrexone eliminates the reinforcing pleasure that drives addictive behaviors. In addition to the branded formulations ReVia, Depade, and Vivitrol (injectable), generic naltrexone tablets are listed in the Singapore Health Sciences Authority’s database and can be ordered through our pharmacy service.

How Naltrexone Works

Mechanism of Action

Naltrexone is a high-affinity competitive antagonist at µ-opioid receptors and, to a lesser extent, κ- and δ-receptors. It occupies the receptor binding pocket, thereby preventing agonists such as morphine, heroin, or endogenous β-endorphins from initiating downstream signaling. This blockade reduces the dopaminergic surge in the mesolimbic reward pathway that underlies craving and relapse.

Therapeutic Effects

By inhibiting µ-receptor activation, naltrexone diminishes the subjective “high” associated with alcohol and opioid intake. In alcohol-dependence, this translates into reduced drinking frequency and quantity, while in opioid relapse prevention it blocks the euphoric effect of illicit use, supporting sustained abstinence. Low-dose naltrexone (typically 1-5 mg daily) appears to modulate immune activity through transient opioid-receptor blockade, a mechanism under investigation for conditions such as multiple sclerosis and fibromyalgia.

Onset and Duration

Oral naltrexone reaches peak plasma concentrations within 1 hour; receptor blockade is evident within 2 hours and persists for approximately 24 hours, justifying once-daily dosing. Clinical trials report a measurable reduction in craving scores as early as the first week of therapy for alcohol-dependence, while opioid-relapse prevention studies show significant differences in relapse rates after 4 weeks of continuous use. The injectable formulation Vivitrol provides a sustained blockade for up to 30 days after a single intramuscular injection.

Approved Uses and Applications

Approved Indications

Alcohol-dependence: Reduces relapse risk and drinking volume when combined with counseling, as demonstrated in a 1995 double-blind trial published in The New England Journal of Medicine showing a 30 % higher abstinence rate versus placebo.
Opioid-dependence (post-detoxification): Prevents opioid-induced euphoria; a 2012 Lancet study reported a 45 % relative reduction in relapse among participants receiving oral naltrexone compared with placebo.

Regulatory bodies such as the FDA, EMA, and Singapore’s HSA list these two indications as the only approved therapeutic uses.

Off-Label Uses

Low-dose naltrexone (LDN) has been investigated for autoimmune diseases (e.g., rheumatoid arthritis, inflammatory bowel disease) and chronic pain syndromes. Small-scale trials published in Autoimmunity Reviews and Pain Medicine indicate modest improvements in pain scores and inflammatory markers, though these applications remain unapproved by the HSA.

Clinical Efficacy

In the COMBINE trial (JAMA, 2003), naltrexone combined with behavioral therapy achieved a 15 % absolute reduction in heavy-drinking days compared with therapy alone. For opioid relapse prevention, a meta-analysis of 14 randomized trials (Cochrane Database, 202) found that naltrexone reduced the odds of relapse by .55 (95 % CI .44-.68). These data underscore its role as a cornerstone of medication-assisted treatment for substance-use disorders.

Buying Naltrexone from Our Online Pharmacy

Why Choose Our Service

Our pharmacy service bridges the gap for patients who encounter stock shortages or high prices at traditional outlets. By sourcing from licensed international partners who comply with WHO Good Manufacturing Practices, we ensure that each tablet meets stringent quality standards while offering competitive pricing.

Brand Names and Generic Options

ReVia® (tablet): Often priced at SGD 85 for a 30-day supply.
Depade® (tablet): Similar cost structure, widely stocked in Southeast Asia.
Vivitrol® (injectable): Longer-acting option priced at SGD 350 per dose.
Generic Naltrexone: Available in 50 mg tablets for as low as SGD 25 per month, delivering the same pharmacological effect as branded products.

Quality & Safety

We partner with accredited pharmacies that operate under the oversight of national regulatory agencies and adhere to the International Council for Harmonisation (ICH) guidelines.

Pricing & Access

Our online service offers a “Lifetime 10 % discount on all reorders,” making chronic therapy more affordable. Bulk purchases of generic tablets can further reduce out-of-pocket costs by up to 40 % compared with local retail pricing.

Discreet Delivery

Orders ship via express courier within 7 days or standard mail in 3 weeks. Packages are sealed in unmarked, tamper-evident envelopes, ensuring privacy for every customer.

Dosing, Formulations & Administration

Available Formulations

Oral tablets are the most common form, supplied in 25 mg and 50 mg strengths. An intramuscular depot injection (Vivitrol) contains 380 mg of naltrexone in a biodegradable polymer matrix.

Typical Dosing Ranges

Alcohol-dependence: Clinicians often start with 50 mg once daily, adjusting based on tolerability.
Opioid-relapse prevention: A standard regimen also begins at 50 mg daily after detoxification, with occasional tapering to 25 mg if side effects arise.
Low-dose off-label use: Doses of 1-4.5 mg daily are reported in research protocols, but such regimens should only be considered under specialist supervision.

Administration Guidelines

Oral tablets should be taken with a full glass of water, preferably in the morning to minimize gastrointestinal upset. food does not significantly affect absorption, but patients with severe hepatic impairment may require dose adjustments. The injectable form is administered by a healthcare professional every 28 days.

Regardless of formulation, a qualified healthcare provider must tailor the exact dose to the individual’s medical history, liver function, and concurrent medications.

Safety Profile & Considerations

Common Side Effects

Nausea: Reported in 15-20 % of participants during the first week.
Headache: Occurs in roughly 10 % of users.
Dizziness: Seen in 8 % of patients, often transient.
Fatigue: Documented in 7 % of trial cohorts.
Insomnia: Affects about 5 % of individuals, usually mild.

These effects are generally self-limiting and diminish with continued therapy.

Serious Adverse Events

Rare but severe reactions include hepatotoxicity (elevated transaminases) and hypersensitivity (rash, pruritus). Immediate medical attention is warranted if jaundice, dark urine, or severe skin reactions develop.

Contraindications

Acute opioid intoxication or dependence without prior detoxification.
Severe hepatic failure (Child-Pugh class C).
Known hypersensitivity to naltrexone or any excipients in the formulation.

Drug Interactions

CYP2C9 inhibitors (e.g., fluconazole) may increase naltrexone plasma levels.
Opioid analgesics (e.g., morphine, oxycodone) will be ineffective and may precipitate withdrawal.
Alcohol combined with naltrexone can still cause central nervous system depression; patients should be counseled on moderation.

Special Populations

Pregnancy: Category B (no evidence of fetal harm in animal studies); however, human data are limited, and clinicians usually avoid use unless benefits outweigh risks.
Breastfeeding: Small amounts pass into breast milk; caution is advised.
Older adults: Reduced hepatic clearance may necessitate lower starting doses.
Renal or hepatic impairment: Dose adjustments are recommended, and liver function tests should be monitored at baseline and periodically.

Professional medical guidance is essential to navigate these considerations safely.

Frequently Asked Questions

How does Naltrexone differ from Naloxone? Naltrexone is an oral or injectable antagonist used for long-term relapse prevention, while naloxone is an injectable agent employed for acute opioid overdose reversal. Their pharmacokinetics and clinical purposes are distinct.
How long before Naltrexone produces noticeable effects for alcohol-dependence? Patients often report reduced cravings within 1 week, with measurable declines in drinking volume emerging after 2-4 weeks of continuous therapy.
What should I do if I experience persistent nausea from Naltrexone? Take the tablet with food or a small snack, stay hydrated, and contact your clinician if symptoms last more than a few days, as dose adjustment may be needed.
Can I take Naltrexone with my current antidepressant medication? No major pharmacokinetic interaction is known with most antidepressants, but serotonergic agents should be discussed with a provider to rule out rare serotonergic syndrome.
Does taking Naltrexone with food affect its absorption? Food does not significantly alter bioavailability; however, a light meal may reduce gastrointestinal discomfort for some users.
Is Naltrexone safe for people with mild liver disease? Mild to moderate hepatic impairment can be managed with regular liver function monitoring; severe liver disease is a contraindication.
How often can I order Naltrexone through your platform? Our service permits unlimited orders, subject to local regulations and supply limits; each purchase includes a discreet, trackable shipment.
What are the advantages of the injectable Vivitrol formulation? Vivitrol provides a once-monthly blockade, eliminating daily pill burden and improving adherence for patients who prefer fewer dosing events.
What should I provide my doctor when discussing Naltrexone?
- Complete list of current medications, including over-the-counter drugs and supplements.
- Detailed medical history, emphasizing liver function and any history of opioid use.
- Specific treatment goals (e.g., reduce drinking, prevent opioid relapse).
- Any prior adverse reactions to opioid antagonists or related agents.

Disclaimer

The information provided about Naltrexone is for general knowledge only. It does not replace professional medical consultation or the official prescribing information for medications containing this ingredient. All treatment decisions, including dosing, formulation selection, and monitoring, should be made under the supervision of a qualified healthcare provider who can assess individual medical history, current medications, and specific health needs. We assume all readers are responsible adults capable of making informed decisions about their health. Our online pharmacy offers access to medications containing Naltrexone for individuals who may have limited availability through traditional pharmacies, prescription-based insurance schemes, or who are seeking affordable generic alternatives. Always consult your doctor before starting, changing, or discontinuing any medication containing Naltrexone.