Esomeprazole for subcutaneous infusion: compatibility with other alkaline medications

INTRODUCTION Several of the palliative medications given subcutaneously are alkaline, including dexamethasone, esomeprazole, parecoxib, sodium valproate and tranexamic acid (alkaline, despite its name). Because pH affects ionisation and thus solubility, it is an important determinant of compatibility; alkaline medications often precipitate in acidic solutions and vice versa. Since most other palliative medications are weak acids, alkaline medications are often administered via separate pumps and cannulae. Following the withdrawal of ranitidine, we selected subcutaneous esomeprazole as an alternative. We audited its introduction and found it to be well tolerated, but encountered circumstances where esomeprazole was required in parallel with other alkaline medicines. This became more common when two parecoxibrelated gastrointestinal bleeds led us to use esomeprazole for gastroprotection more often. Thus, in some patients, multiple separate infusions presented practical challenges. After observing an absence of visible precipitation in alkaline admixtures kept for 24 hours, we discussed the risks and benefits of rationalising multiple infusions into single alkaline admixtures with selected patients. We went on to audit the use of subcutaneous alkaline admixtures.