Naltrexone Capsule

Naltrexone Capsules
Usage
Naltrexone capsules are an oral opioid receptor antagonist used in the management of substance dependence and, at lower doses, certain chronic conditions under specialist supervision.
They may be prescribed for:
• Alcohol dependence – to reduce cravings and relapse risk
• Opioid dependence – to prevent opioid effects after detoxification
• Low-dose naltrexone (LDN) therapy (off-label), for:
• Chronic pain conditions
• Autoimmune disorders
• Inflammatory conditions
Use should be under the supervision of a qualified healthcare professional.

Dosage
Dosage should be determined by the prescribing practitioner based on the indication and patient response.
Typical dosing considerations include:
• For dependence: usually once daily dosing, or as directed
• For low-dose therapy: typically lower doses taken once daily, often at night
• Capsules should be swallowed whole with water
• May be taken with or without food
Patients must be opioid-free for an appropriate period before starting therapy to avoid withdrawal.

Mechanisms of Action
Naltrexone is an opioid receptor antagonist.
Its mechanisms include:
Blockade of opioid receptors (μ, κ, δ)
Naltrexone competitively binds to opioid receptors, preventing activation by opioids.
Reduction of reward effects
In alcohol and opioid dependence, it reduces the reinforcing and rewarding effects of substance use.
Endorphin modulation (low-dose use)
At low doses, naltrexone may transiently block opioid receptors, leading to a rebound increase in endogenous endorphins, which may modulate immune and pain pathways.

Contraindications
Naltrexone should not be used in patients with:
• Current opioid use or dependence
• Acute opioid withdrawal
• Hypersensitivity to naltrexone or formulation components
• Acute hepatitis or severe liver failure

Precautions
Naltrexone should be used with caution in patients with:
• Hepatic impairment, as naltrexone may affect liver function
• Renal impairment
• History of depression or psychiatric conditions
Additional considerations include:
• Patients must avoid opioid-containing medications, as naltrexone blocks their effects
• Attempting to override the blockade with high doses of opioids can lead to serious toxicity or overdose
• May cause side effects such as:
• Nausea
• Headache
• Fatigue
• Sleep disturbances
• Liver function may need to be monitored during treatment
Patients should seek medical advice if they experience abdominal pain, jaundice, mood changes, or signs of withdrawal.

Storage
• Store below 25°C unless otherwise directed
• Keep capsules in a tightly closed container
• Protect from heat, moisture, and direct light
• Keep out of reach of children and pets
Patients should follow the storage instructions provided on the dispensing label supplied by the pharmacy.