Ketorolac was administered to 15 healthy volunteers in a phase 1, single-dose, crossover, randomized study. Subjects received open-label randomized 15- and 30-mg intramuscular (i.m.) ketorolac and blinded randomized 15- and 30-mg intranasal (i.n.) ketorolac. The i.n. ketorolac was well tolerated; the only nasal symptoms were some instances of mild irritation. The i.n. ketorolac was rapidly and well absorbed (median tmax, 0.50-0.75 hours), and the half-life was approximately 5 to 6 hours, values that were similar to those following i.m. administration. Relative bioavailability of i.n. compared to i.m. administration at the same doses was approximately 67% to 75%. Dose proportionality was noted between the 15- and 30-mg i.n. and i.m. dose levels. Thus, i.n. ketorolac offers a therapeutic alternative to i.m. administration and may provide benefits in the clinical setting.