Stability and compatibility of baclofen and morphine admixtures for use in an implantable infusion pump

The simultaneous intrathecal infusion of baclofen and morphine may be of significant benefit in the treatment of both severe pain and spasticity. The stability and physical compatibility of baclofen and morphine admixtures, at a range of concentrations relevant to their use for intrathecal administration, have been examined. The studies reported demonstrate that baclofen and morphine in the admixtures examined were stable for at least 30 days when stored at 37°C. In addition, it was shown that admixtures can be introduced into an Infusaid^® implantable infusion pump, used clinically for the intrathecal delivery of drugs, and appropriate concentrations of both baclofen and morphine maintained for a duration of up to 30 days. The data presented indicate that admixtures of baclofen and morphine can be successfully prepared and delivered using an Infusaid^® pump for periods consistent with proposed clinical practice.