Objective: To evaluate the stability of reconstituted INDOCIDR P.D.A. Rationale: Although slow, continuous infusion of indomethacin has been used for the treatment of PDA (Pediatrics 1995;95:244), there are no published data on the stability of the reconstituted drug. The manufacturer recomments that any unused portion of the solution be discarded after a 5-10 second injection. Methods: The stability of INDOCIDR P.D.A. in sterile water (0.5 mg/mL) was evaluated during a 14-day storage period at either 4°C or 23°C in the original vial and in 1 mL disposable polypropylene syringes, using a validated, liquid chromatographic method. Physical inspection and determinations of pH were also completed on each of 9 study days. Regression analysis was used to examine the relationship between drug concentration and storage time. Results: All solutions retained > 90% of the initial indomethacin concentration during the 14-day period. However, in contrast to solutions stored at 4°C those kept at 23°C contained small amounts of degradation products. The pH at either temperature did not change by more than 0.8 of a pH unit in any solution during the study period. Conclusions: INDOCIDR P.D.A. in sterile water can be stored at 4°C for up to 14 days in the original vial or in 1 mL polypropylene syringes. Solutions should be kept at room temperature only for a short period of time (< 12 hours). Any storage of reconstituted indomethacin and the prescription of continuous drug infusions require due consideration of sterility and of the rate of contamination in an IV additive program. (Supp by MRC Canada)