A double-blind, placebo-controlled study in patients undergoing lumbar laminectomy was carried out to assess the morphine-sparing effect of a controlled-release indomethacin formulation ('Flexin Continus' tablets, 75 mg). Thirty patients were randomly allocated to receive 1 tablet of active or placebo study medication pre-operatively and their pain scores on visual analogue scale (VAS) and their morphine consumption, delivered by Patient Controlled Analgesia (PCA), were recorded over the 24-hour post-operative period. Over the first 4-hour post-operative period, the patients who had received active treatment reported less pain on VAS than those in the placebo group and this difference was statistically significant on recovery (p = 0.033) and at 1 hour post-recovery (p = 0.013). By 4, 8, 12 and 24-hours post-recovery the mean cumulative amount of morphine used by patients in the active treatment group was reduced by 25%, 23%, 37% and 30%, respectively, compared to the control group. At the 12-hour time point, the difference in morphine consumption approached statistical significance (p = 0.074). It is concluded that the pre-operative administration of controlled-release indomethacin reduces post-operative morphine requirements and significantly reduces VAS pain scores on recovery.