Background and importance Death rattle occurs in 25–90% of dying patients and is often associated with pulmonary fluid overload. Co-administration of scopolamine (anticholinergic drug) and bumetanide (loop diuretic) could be used to avoid unnecessary fluid overload at the end stage of life.

Aim and objectives The study aimed to investigate the physical and chemical stabilities of the admixture bumetanide and scopolamine, prepared in advance, by a centralised intravenous additive service (CIVAS) in the hospital pharmacy.

Material and methods Stability of minimal (min) concentration was evaluated for five polypropylene syringes of 48 mL containing the admixture bumetanide (Burinex 2 mg/4 mL, Leo, Belgium) and scopolamine (0.25 mg/mL, Sterop, Belgium) at 41.67 µg/mL and 5.21 µg/mL, respectively. The maximal (max) concentration with 125 µg/mL of bumetanide and 31.25 µg/mL of scopolamine was evaluated for five polypropylene syringes of 14 mL. All syringes were stored for 18 days at 5±3°C. Periodic samples were visually and microscopically examined to observe any particle appearance or colour change. pH and absorbance at three wavelengths (350, 410 and 550 nm) were monitored. The concentrations were measured by ultra-high performance liquid chromatography–photodiode array detection.

Results Over 18 days, there was no change in colour or appearance of opacity, turbidity or precipitation, and the pH remained stable. The relative concentrations of bumetanide and scopolamine at min and max concentrations after 18 days were unchanged, with 100.1% and 100.3% of the initial content of bumetanide and with 99.2% and 99.4% of the initial content of scopolamine. The lower limits of the 90% CI on the means of both molecules at min and max concentrations remained higher than the 90% threshold that considers the mixture to be chemically stable.

Conclusion and relevance The study is the first to show that the admixture of bumetanide and scopolamine is physically and chemically stable at two concentrations used in the palliative care unit. This combination, available in polypropylene syringes, has numerous advantages (eg, preparation under aseptic conditions by a CIVAS with decreased workload and preparation errors).

Conflict of interest No conflict of interest