precipitation of drugs

Last reviewed 01/2018

Precipitation may occur due to:

  • drug incompatibility (discard if solution precipitates
  • too concentrated solution or is discoloured)
  • use of saline instead of Water for Injection


  • check BNF for compatibility
  • use large enough volumes
  • dilute while preparing

Drugs requiring care:

  • Dexamethasone: dilute carefully when preparing
  • Cyclizine: precipitates above concentration 10mg/ml after 24 hours, in saline, and in higher concentrations of Diamorphine
  • Haloperidol: precipitates above concentration of 2mg/ml after 24 hours in mixtures with Diamorphine