NALTREXONE

Opioid receptor antagonist that precipitates withdrawal symptoms in opioid dependent patients

Dosage Forms

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Tablet

50 mg

Uses

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  • Adjunct to prevent relapse in formerly opioid-dependent patients (opioid free for at least 7–10 days)
  • Adjunct to prevent relapse in formerly alcohol-dependent patients

Dose and Duration

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Relapse prevention in opioid dependence

Base treatment on result of the ‘naloxone test’ (see naloxone)

Adult above 18 years: initially, 25 mg once daily then 50 mg once daily. Total weekly dose 350 mg may be divided and given on 3 days of the week for improved compliance (max dose per day 150 mg) for 3 months or longer as may be necessary

Relapse prevention in alcohol dependence

Adult: 25 mg on first day, increased to 50 mg daily if tolerated

Contraindications

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  • Patients currently dependent on opioids
  • Acute hepatitis and severe hepatic impairment
  • Severe renal impairment

Side Effects

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  • Abdominal pain, nausea, vomiting, diarrhoea
  • Constipation
  • Anxiety, sleep disorders, loss of appetite
  • Tachycardia, palpitations, abnormal ECG
  • Dizziness, headache, fatigue, restlessness, weakness
  • Increased lacrimation, sweating, chills, hot flushes
  • Chest pain, dyspnoea
  • Rash, dermatitis, pruritus
  • Urinary retention
  • Delayed ejaculation, libido disorders
  • Joint and muscle pain
  • Thirst, increased energy, weight loss, weight gain

Patient Instructions

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  • Do not try to overcome effects of the medicine by over-dosing on opioids; this will lead to acute opioid toxicity
  • Do not take any opioid containing preparations like in cough preparations and loperamide during treatment
  • Swallow your tablets with water

Pregnancy

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  • Do not use

Breast-feeding

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  • Do not use

⚠️ Caution

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  • Review treatment monthly for the first 6 months, and then at reduced intervals
  • Stop naltrexone if patient continues taking alcohol for 4–6 weeks after starting treatment
  • Carry out liver function tests before and during treatment
  • Test for opioid dependence using naloxone before commencing treatment with naltrexone
  • Avoid concomitant use of opioids. In case large dose of opioid is needed for pain, monitor patient for intoxication
  • Only use in pregnancy if benefit outweighs risk; risk of acute withdrawal with possibly serious side effects to mother and foetus