Intramuscular Ketorolac at Two Single-Dose Regimens

Inclusion Criteria: * Tricare beneficiaries between 18-55 years of age * Triaged as Emergency Severity Index 4 or 5 * Presenting to the William Beaumont Army Medical Center Emergency Department with a chief complaint of acute MSK pain (i.e., general muscular, neck, back, shoulder, arm, forearm, elbow, wrist, finger, hip, knee, thigh, leg, ankle, foot, or digits) * Pain intensity of 20 mm or greater on a standard 100 mm visual analog scale * Who the attending provider concurred with ketorolac IM administration for analgesia. Exclusion Criteria: * Body weight less than 50 kg (110 lbs.) * Younger than 18 or older than 55 years * Pregnant or breast feeding * History of: confirmed, unconfirmed, known, unknown, or suspected peptic ulcer disease, intestinal hemorrhage, renal insufficiency, hepatic insufficiency, cerebrovascular bleeding, hemorrhagic diathesis, incomplete hemostasis, dark stools, bright red blood per rectum, hemoptysis, easy bruising, or high risk of bleeding * Unable to confidently convey or unknown medical history * Allergy or hypersensitivity to nonsteroidal anti-inflammatory drugs or aspirin * Systolic blood pressure \<90 or \>180 mmHg * Pulse rate \<50 or \>150 beats/min * Any over-the-counter or prescribed opioid and/or non-opioid analgesic medication (oral, per rectum, topical or parenteral) taken within 12 hours of ED presentation * Advised by any medical provider to not receive NSAIDs for any reason * Pain duration greater than 30 days (including acute on chronic pain) * Refusal to remain in the WBAMC ED for up to 60 minutes after injection of ketorolac * Patients currently taking anticoagulant medications * Concurrent use of medications which are contraindicated with concomitant NSAID use (drugs include aspirin, probenecid and pentoxifylline).