What is the appropriate intramuscular dose of ketorolac for an acute migraine attack in an adult patient, and what are its contraindications?

IM Ketorolac Dosing for Migraine

While ketorolac IM can be used for acute migraine, it is NOT a first-line or preferred agent according to the most recent 2025 American College of Physicians guidelines, which recommend NSAIDs (oral) and triptans as primary therapy 1. However, when parenteral therapy is needed in emergency settings, ketorolac IM should be dosed at 60 mg for adults <65 years, or 30 mg for adults ≥65 years, renally impaired, or <50 kg body weight 2.

Dosing Specifics

Single-Dose IM Administration

• Adults <65 years: 60 mg IM as a single dose 2
• Adults ≥65 years, renally impaired, or <50 kg: 30 mg IM as a single dose 2
• Administer slowly and deeply into the muscle 2
• Onset of analgesia begins in ~30 minutes, peaks at 1-2 hours, duration 4-6 hours 2

Multiple-Dose Regimen (if needed)

• Adults <65 years: 30 mg IM every 6 hours (maximum 120 mg/day) 2
• Adults ≥65 years, renally impaired, or <50 kg: 15 mg IM every 6 hours (maximum 60 mg/day) 2
• Total duration must not exceed 5 days for combined parenteral and oral ketorolac 2

Evidence Context

The 2025 American Headache Society guideline rates ketorolac IV as "likely effective" (level B - should offer) for ED migraine treatment 3, though this is based on IV rather than IM data. A 2013 systematic review found ketorolac effective for acute migraine but possibly less effective than metoclopramide/phenothiazine agents 4. Recent 2023 evidence suggests lower doses (15-20 mg) may be as effective as higher doses (≥30 mg) for acute pain, though patients may require more rescue analgesia 5.

Major Contraindications

Absolute contraindications per FDA labeling 2, 6:

• Active or history of gastrointestinal bleeding or perforation
• Active peptic ulcer disease
• Advanced renal impairment or risk of renal failure (correct hypovolemia before administration)
• History of hypersensitivity to aspirin or other NSAIDs (including asthma, urticaria, or allergic reactions)
• Perioperative pain in CABG surgery
• Labor, delivery, and nursing mothers
• Compromised hemostasis or coagulation disorders
• Concurrent use with other NSAIDs (including aspirin)
• Cerebrovascular bleeding or hemorrhagic diathesis

High-Risk Populations Requiring Dose Adjustment

• Age ≥65 years (increased GI bleeding risk) 2, 6
• Renal impairment (risk of acute renal failure) 2, 6
• Body weight <50 kg 2
• Patients on anticoagulants (increased bleeding risk) 6

Critical Clinical Pitfalls

1. Duration limit: Never exceed 5 days total therapy (parenteral + oral combined) - this is when serious adverse events increase significantly 2, 6

2. Medication overuse headache: NSAIDs used ≥15 days/month can cause rebound headaches 1

3. Not first-line for outpatient migraine: The 2025 ACP guideline emphasizes oral NSAIDs + triptans as preferred initial therapy; parenteral ketorolac is reserved for ED/acute care settings where oral therapy has failed or is not feasible 1

4. Renal function: Always assess hydration status and correct hypovolemia before administration to minimize renal toxicity risk 2

5. Drug incompatibility: Do not mix ketorolac in the same syringe with morphine, meperidine, promethazine, or hydroxyzine - causes precipitation 2

6. Consider alternatives: The 2025 AHS guideline rates prochlorperazine IV and greater occipital nerve blocks as "must offer" (level A) treatments in ED settings, suggesting these may be superior options when parenteral therapy is needed 3