Thanks to Salim Rezaie for guest editing this post which is cross-posted on REBEL EM.
Ketorolac is a commonly used parenteral analgesic in the Emergency Department (ED) for a variety of indications ranging from musculoskeletal injuries to renal colic. This non steroidal anti-inflammatory drug (NSAID) is available in oral, intranasal and parenteral routes. Ketorolac has a number of side effects including nausea, vomiting, gastrointestinal bleeding and renal insufficiency. The risk of GI bleeding appears to be related to the use of higher doses and prolonged use. As with all NSAIDs, the drug has an analgesic ceiling – the dose at which additional dosing will not provide additional analgesia but can lead to more side effects. The current FDA dosing is 30 mg intravenously and 60 mg intramuscularly for patients < 65 years of age. However, the necessity of these doses is unclear and prior studies have demonstrated efficacy of considerably lower doses. The use of lower doses, if effective, may mitigate the potential for harm.
Do higher doses of IV ketorolac provide improved analgesia in the ED?
Patients 18 – 65 years of age presenting to the ED with acute flank, abdominal, musculoskeletal or headache pain that was >/= 5 on a standard 10 point pain scale in whom the attending physician though ketorolac would be an appropriate medication choice.
10-, 15- or 30- mg doses of ketorolac prepared in identical syringes
Primary: Pain reduction at 30 minutes
Secondary: Rates and percentages of subjects experiencing adverse effects and requiring rescue analgesia
Single-center, randomized, double-blind trial performed at a large urban ED.
Age > 65
Pregnancy or breastfeeding
Active peptic ulcer disease
Acute GI hemorrhage
Known renal or hepatic insufficiency
Allergy to NSAIDs
Unstable vital signs
Patients that had already received an analgesic
- Enrollment: 24o patients (80 in each group)
- 312 patients approached, 72 refused to participate
- All 240 patients included in analysis
Pain Reduction at 30 Minutes (Primary Outcome)
- 80% power to detect a 1.3 point difference in pain score at 30 minutes
- 10mg Group: Pain score 7.7 —> 5.2 (diff 2.5)
- 15 mg Group: Pain score 7.5 —> 5.1 (diff 2.4)
- 30 mg Group: Pain score 7.8 —> 4.8 (diff 3.0)
- No statistically or clinically significant difference between doses
- Adverse Events
- No significant events in any group
- Common events were dizziness and nausea which were equal across groups
- Need for rescue analgesia was not different across groups
- Study asks a clinically important question with a patient centered outcome
- Randomization conducted by computer generation and blinding was appropriate
- Clinically relevant adverse events were tracked
- For the primary endpoint, only 2 data points were missing out of 240 patients
- Single center study decreasing external application of results
- Convenience sampling used introducing selection bias
- Study is too small to comment on rare or uncommon adverse events
- The study investigates the analgesic ceiling effect but does not provide information regarding the anti-inflammatory ceiling.
“Ketorolac has similar analgesic efficacy at intravenous doses of 10, 15, and 30 mg, showing that intravenous ketorolac administered at the analgesic ceiling dose (10 mg) provided effective pain relief to ED patients with moderate to severe pain without increased adverse effects.”
This high-quality RDCT demonstrates that the analgesic ceiling for ketorolac appears to be 10 mg if given intravenously. Administration of higher doses is unlikely to improve analgesic results.
Potential Impact To Current Practice
The results and conclusions of this study implore providers to embrace lower dosing of ketorolac than what is standardly employed (i.e. 30 mg IV). This study did not find an increase in adverse events with the higher dosing of ketorolac but, the study was too small to establish safety. Additionally, if there is no added benefit to analgesia of higher doses, higher doses only hold potential for harm.
Based on the best available literature at this time, providers should switch to giving 10 mg of ketorolac IV for acute pain in the ED.
PharmERToxGuy: The Ceiling Effect of IV Ketorolac
SOCMOB Blog: NSAID Part 2: The Ceiling Effect