Subcutaneous Dihydrocodeine Tartrate: Compatibility in a Syringe Pump With Other Drugs Frequently Prescribed for the Management of Symptoms Associated With Brain Tumors.

Background: Dihydrocodeine can be more effective in the management of headache due to brain tumor than other opioids. It can be used as a subcutaneous infusion, but at present, there is little available data to support its use in combination with other medicines in a syringe pump.

Aim: This project aimed to establish physical stability data for the use of dihydrocodeine with other drugs when combined in a syringe pump. Design: Dihydrocodeine was combined in a syringe pump with either cyclizine, midazolam, or hyoscine butylbromide at different doses chosen to represent routine clinical practice. Each drug combination was repeated twice-with 0.9% sodium chloride and with water for injections. Setting: The project was conducted in an independent hospice after seeking appropriate approvals to use the drugs for this purpose.

Results: Dihydrocodeine and midazolam appear compatible at when 0.9% sodium chloride is used as the diluent. Dihydrocodeine and cyclizine appeared compatible when either 0.9% saline or water for injections was used as the diluent. Dihydrocodeine and hyoscine butylbromide appeared compatible with either diluent at 24 hours.

Conclusions: Physical stability data has been described that will support the use of dihydrocodeine and other drugs that are commonly used to manage symptoms due to brain tumors at the end of life. This information will benefit patients and ensure that one syringe pump can be used where possible. Future work could expand on this data and explore the physical stability of three drug combinations in each syringe.