Naltrexone oral liquid formula

Naltrexone 1 mg/mL (100 mL)


  • Naltrexone 100 mg (2 x 50 mg tablets)
  • Ascorbic acid 500 mg (powder or crushed tablets)
  • Preservative 0.1% (e.g. 1 mL compound hydroxybenzoate solution or 1 mL methyl hydroxybenzoate 10% solution: formula on Pharmac website)
  • Glycerol 20 mL
  • Water to 100 mL


  • Crush naltrexone tablets and triturate with ascorbic acid
  • Add glycerol and preservative to make a paste
  • Make up to final volume with water

Storage and notes

  • Stable for 30 days at room temperature or 60 days in the fridge
  • The liquid is very bitter and gritty, if necessary the dose can be mixed with juice or another flavoured drink just prior to administration.

Reproduced with permission from Dave Woods: Fawcett JP, Morgan NC, Woods DJ. Formulation and Stability of Naltrexone Oral Liquid for Rapid Withdrawal from Methadone. Annals of Pharmacotherapy. 1997;31(11):1291-1295.