Long-acting μ-opioid antagonist
Naltrexone hydrochloride
Brand names: Adepend, Nalorex
Adult dose
Dose: Alcohol/opioid dependence: 25mg OD initially, then 50mg OD
Route: PO
Frequency: OD
Clinical pearls
- Opioid-free for ≥7–10 days before starting (verify with naloxone challenge)
- Alcohol-dependence relapse prevention
- Counsel that opioid analgesia will not work — use NSAIDs/regional anaesthesia for acute pain
Contraindications
- Concurrent opioid use
- Acute hepatitis
- Severe hepatic/renal impairment
- Hypersensitivity
Side effects
- Nausea
- Headache
- Insomnia
- Hepatotoxicity (high dose)
- Precipitated withdrawal if recent opioid use
Interactions
- Opioids (no analgesia; severe withdrawal)
Monitoring
- LFTs
- Mental state
Reference: BNF; NICE CG115; PHE drug misuse guidelines; https://bnf.nice.org.uk/drugs/naltrexone-hydrochloride/. Verify against your local formulary and the latest BNF before prescribing.
Related
Curated clinical cross-links plus same-class fallbacks.
Calculators
- Morphine Milligram Equivalents (MME) Calculator · Pain / Opioids
- Opioid Conversion / Equianalgesic Guide · Pain Management
- Corrected QT Interval (Bazett) · ECG
- Bazett Corrected QT Interval (QTc) Calculator · Arrhythmia
- Long QT Syndrome (Schwartz Score) · Channelopathy / Sudden Cardiac Death
- Numeric Rating Scale (NRS) Pain Assessment and Management · Pain Management
Pathways
- Acute Psychosis Management · NICE CG178 2014
- Depression Management · NICE CG90 2022
- Lithium Therapy Monitoring · NICE CG185 / BNF
- Alcohol Withdrawal Management · NICE CG115 2010 / BNF
- Eating Disorder Assessment · NICE CG9 2017 / MARSIPAN
- Serotonin syndrome · Hunter criteria (Dunkley 2003); TOXBASE/NPIS; BNF