naltrexone hydrochloride: clinical use

Prescribing considerations

• Use within a comprehensive psychosocial treatment and recovery plan.
• Confirm opioid freedom before initiation; do not initiate during withdrawal or after a positive opioid test.
• Plan non-opioid analgesia and explain overdose risk from attempts to overcome blockade and from reduced opioid tolerance after treatment.
• Use caution and close supervision in mild or moderate hepatic or renal impairment.

Contraindications and cautions

• Hypersensitivity to naltrexone or an excipient
• Acute hepatitis, liver failure, or severe or acute hepatic impairment
• Severe renal impairment
• Current opioid analgesic or opioid-containing medicine use
• Methadone treatment
• Current opioid dependence or acute opioid withdrawal
• Positive opioid test or withdrawal following a naloxone challenge

Monitoring

• Assess hepatic and renal function before treatment; repeat liver testing according to clinical risk and product guidance.
• Monitor treatment response, adherence, substance use and engagement with psychosocial support.
• Monitor mood, depression and suicide risk.

Clinical pharmacology

Naltrexone is a competitive opioid-receptor antagonist. It undergoes substantial first-pass hepatic metabolism to active 6-beta-naltrexol and is excreted mainly through the kidneys.

Formulation and product differences

• The selected product is a capsule-shaped, film-coated, scored tablet that can be divided into equal halves.
• It contains lactose and is unsuitable for people with rare hereditary galactose intolerance, total lactase deficiency or glucose-galactose malabsorption.