What is naltrexone used for?

Naltrexone is FDA-approved at standard doses to treat alcohol use disorder and to help prevent relapse in people who have stopped using opioids. Low Dose Naltrexone (LDN) 4mg is a compounded form prescribed off-label by some providers for conditions such as chronic pain and fibromyalgia.

Do I need a prescription for Low Dose Naltrexone 4mg?

Yes. Naltrexone in any strength requires a valid prescription from a licensed U.S. healthcare provider. Our pharmacists verify every prescription before dispensing.

How does ordering and shipping work?

After you submit your prescription, a licensed provider or pharmacist reviews it for safety and accuracy. Once approved, your medication is filled and shipped from a licensed U.S. pharmacy to your address.

Is Low Dose Naltrexone the same as regular naltrexone?

It is the same active ingredient at a much lower dose. Standard naltrexone tablets are typically 50mg, while LDN capsules are compounded at low strengths such as 4mg for off-label uses; the 4mg strength is not an FDA-approved product.

Can I take naltrexone if I am using opioid pain medication?

No. Naltrexone blocks opioids and can trigger sudden, severe withdrawal in people who are opioid-dependent. Tell your provider about all opioid-containing medicines, including cough and antidiarrheal products, before starting.

What are the most common side effects of naltrexone?

Common side effects include nausea, headache, dizziness, trouble sleeping, vivid dreams, and fatigue. Contact your provider if side effects persist or if you notice signs of liver problems such as yellowing skin or dark urine.

How long does naltrexone take to work?

Response varies by condition and individual. For off-label low-dose use, some providers evaluate response over several weeks; follow your prescriber's guidance and attend follow-up visits.

Naltrexone 4mg

Name: Naltrexone 4mg
Brand: All Family Pharmacy
SKU: naltrexone-4mg
Availability: InStock

Generic For: Low Dose Naltrexone

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Naltrexone is an opioid antagonist that is FDA-approved at standard doses to treat alcohol use disorder and to help prevent relapse to opioid dependence. Low Dose Naltrexone (LDN) 4mg capsules are a compounded, prescription-only formulation that some providers prescribe off-label for conditions such as chronic pain and fibromyalgia. After a licensed provider reviews your prescription, your order ships from a licensed U.S. pharmacy.

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Buy Naltrexone 4mg (Low Dose Naltrexone) Online

An opioid antagonist used for alcohol use disorder and opioid dependence, prescribed at low doses off-label for chronic pain and inflammatory conditions

Medically reviewed by David Paul Mackarey, RPh, Pharmacist-in-Charge

Naltrexone 4mg Quick Facts

Drug class	Opioid antagonist
Treats	Alcohol use disorder, opioid dependence; off-label low-dose use for chronic pain
Form	Capsule
Typical dosing	Take 1 capsule by mouth daily
Prescription required	Yes — prescription only

What Is Naltrexone 4mg?

Naltrexone is a medication that blocks opioid receptors in the brain. At the standard 50mg dose, it is FDA-approved to treat alcohol use disorder and to block the effects of opioids in people who have stopped using them. Low Dose Naltrexone (LDN) 4mg is a compounded capsule prescribed off-label; researchers believe very low doses may modulate the immune system and pain signaling. LDN requires a valid prescription and is not an FDA-approved product at this strength.

What Does Naltrexone 4mg Treat?

Alcohol use disorder (FDA-approved at standard doses)
Blockade of opioid effects after opioid detoxification (FDA-approved at standard doses)
Chronic pain, including fibromyalgia (off-label, low dose)
Inflammatory and autoimmune-related symptoms (off-label, low dose)
Crohn's disease symptom support (off-label, low dose)
Multiple sclerosis symptom support (off-label, low dose)

Naltrexone 4mg Dosage

FDA-approved naltrexone: 50 mg by mouth once daily.
Low Dose Naltrexone 4mg: 1 capsule by mouth once daily, or as directed by your prescriber (off-label; compounded strength).

Your prescriber will determine the dose and duration that are right for you. Always follow the directions on your prescription label.

Naltrexone 4mg Side Effects

Common side effects

Nausea
Headache
Dizziness
Trouble sleeping or vivid dreams
Fatigue
Anxiety or nervousness
Stomach pain or cramps
Decreased appetite

Serious side effects

Stop taking this medication and seek medical attention right away if you experience:

Signs of liver injury (yellowing skin or eyes, dark urine, severe stomach pain)
Severe allergic reaction (rash, swelling, difficulty breathing)
Depression or suicidal thoughts
Precipitated opioid withdrawal (agitation, sweating, vomiting)
Severe injection-site or skin reactions

Warnings & Interactions

Do not use if currently taking opioids or dependent on opioids; can cause sudden withdrawal.
Do not use during acute opioid withdrawal.
Avoid opioid-containing medicines (pain relievers, cough medicines, antidiarrheals) while taking naltrexone.
Use caution with liver disease; naltrexone may affect liver function.
Attempting to overcome the opioid blockade with high opioid doses can cause fatal overdose.
Tell your provider if you are pregnant, planning pregnancy, or breastfeeding.
Low Dose Naltrexone 4mg is a compounded product used off-label; discuss risks and benefits with your prescriber.

Tell your prescriber about all medications, supplements, and health conditions before starting naltrexone 4mg.