Motov et al. "Comparison of Intravenous Ketorolac at Three Single-Dose Regimens for Treating Acute Pain in the Emergency Department: A Randomized Control Trial." Annals of Emergency Medicine. December 2016.

Study Design: Randomized, double-blind trial of 240 patients to assess the efficacy of 3 doses of intravenous ketorolac (10 mg, 15 mg, 30 mg) in patients with a pain score greater than or equal to 5 on numeric rating scale.
Primary Outcome: Pain reduction at 30 minutes from medication administration
Secondary Outcomes: Rates of rescue analgesia, Adverse events
Results:

• At 30 minutes, "substantial pain reduction was demonstrated without any differences between the groups."

• 10 mg group: Baseline pain score = 7.7, 30 minute score = 5.1 (95% CI 4.5-5.7)

• 15 mg group: Baseline pain score = 7.5, 30 minute score = 5.0 (95% CI  4.5-5.6)

• 30 mg group: Baseline pain score = 7.8, 30 minute score = 4.8 (95% CI 4.2-5.4)

• Rates of rescue anaglesia were similar in all three groups

• Rates of adverse events were similar in all three groups

Conclusion: IV ketorolac provides similar analgesic efficacy for moderate to severe pain at doses of 10 mg, 15 mg, and 30 mg. The evidences supports a lower analgesic ceiling for IV ketorolac at 10 mg.