Ketorolac Dosage for Acute Low Back Pain
For an adult with acute low back pain and no contraindications, ketorolac should be dosed at 10 mg orally every 4-6 hours as needed (maximum 4 doses daily, not to exceed 5 days total duration), based on FDA-approved dosing and clinical trial evidence demonstrating superior tolerability compared to opioid alternatives. 1, 2
Oral Dosing Regimen
- Ketorolac 10 mg orally every 4-6 hours as needed is the recommended outpatient dose for acute low back pain, with a maximum of 40 mg per day 2
- Treatment duration should not exceed 5 days due to increased risk of gastrointestinal and renal adverse events with prolonged use 1, 3
- Analgesic effect begins within 30 minutes, with maximum effect at 1-2 hours and duration of 4-6 hours 1
Parenteral Dosing (If Applicable in Emergency Settings)
- For patients <65 years: 30 mg IV (over ≥15 seconds) or 60 mg IM as a single dose, or 30 mg IV/IM every 6 hours for multiple doses (maximum 120 mg/day) 1
- For patients ≥65 years, renally impaired, or <50 kg: 15 mg IV or 30 mg IM as a single dose, or 15 mg IV/IM every 6 hours for multiple doses (maximum 60 mg/day) 1
- Patients should be transitioned to oral analgesics as soon as possible 1
Evidence Supporting Ketorolac for Low Back Pain
- A randomized controlled trial demonstrated that ketorolac 10 mg provided comparable analgesic efficacy to acetaminophen-codeine (600 mg/60 mg) for acute low back pain, but with significantly fewer adverse events and no withdrawals due to side effects (compared to 7 withdrawals in the opioid group) 2
- Ketorolac has analgesic efficacy similar to morphine and other opioids for acute pain, with a potentially longer duration of effect 4, 3
- NSAIDs (including ketorolac) are recommended as first-line pharmacologic therapy for acute low back pain by the American College of Physicians, with evidence for short-term symptomatic relief 5
Critical Safety Considerations
- Gastrointestinal risk: Monitor for signs of bleeding, especially in elderly patients or those with prior ulcer history; consider co-administration with a proton-pump inhibitor in high-risk patients 5, 3
- Renal risk: Avoid in patients with significant renal impairment (eGFR <30 mL/min); ensure adequate hydration before administration 1, 3
- Cardiovascular risk: Use the lowest effective dose for the shortest duration; assess cardiovascular risk factors before prescribing 6, 3
- Bleeding risk: Ketorolac reversibly inhibits platelet aggregation; avoid in patients on anticoagulants or with bleeding disorders 4, 3
- Duration limit: The risk of serious gastrointestinal or operative site bleeding increases markedly when high doses are used for more than 5 days, especially in elderly patients 3
Clinical Context and Alternatives
- NSAIDs are slightly more effective than acetaminophen for acute low back pain, though acetaminophen has a more favorable safety profile for patients with cardiovascular risk factors 5, 7
- Opioids should be reserved only for severe, disabling pain not controlled by NSAIDs or acetaminophen, given lack of superiority and higher adverse event profile 5
- Muscle relaxants can be added for short-term relief (1-2 weeks) if NSAIDs provide inadequate pain control, though they cause significant sedation 7, 8
Common Pitfalls to Avoid
- Do not exceed 5 days of treatment with ketorolac, as serious adverse events increase significantly beyond this duration 1, 3
- Do not use in patients already taking other NSAIDs to avoid additive toxicity 1
- Do not mix ketorolac injection with morphine, meperidine, promethazine, or hydroxyzine in the same syringe, as this causes precipitation 1
- Do not assume all NSAIDs are equivalent—ketorolac has particularly potent analgesic effects but also requires strict duration limits unlike other oral NSAIDs 4, 3