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Nonsteroidal anti-inflammatory drug (NSAID)

Ketorolac

Ketorolac is a potent nonselective NSAID used for short-term management of moderate-to-severe acute pain, typically limited to 5 days due to significant gastrointestinal and renal risks. It inhibits both COX-1 and COX-2 enzymes, providing analgesia comparable to opioids without respiratory depression. The most testable fact is its contraindication in patients at risk for bleeding and its strict duration limit.

Practice questionsHigh-yield facts
Drug classNonsteroidal anti-inflammatory drug (NSAID)
MechanismNonselective COX-1 and COX-2 inhibition, reducing prostaglandin synthesis
Main usesShort-term moderate-to-severe acute pain management
Key adverse effectGastrointestinal bleeding and renal impairment
7 min readFor medical studentsUpdated 2026-10-14

Mechanism of action

Ketorolac is a nonselective cyclooxygenase (COX) inhibitor that blocks both COX-1 and COX-2 enzymes. By inhibiting these enzymes, ketorolac prevents the conversion of arachidonic acid to prostaglandins and thromboxanes, key mediators of inflammation, pain, and fever.

COX-1 inhibition reduces constitutive prostaglandin production in the gastric mucosa, kidneys, and platelets, which accounts for many of ketorolac's adverse effects including gastric ulceration, renal dysfunction, and impaired platelet aggregation. COX-2 inhibition reduces inducible prostaglandin synthesis at sites of inflammation and injury, providing the analgesic and anti-inflammatory effects.

Ketorolac has potent analgesic properties with relatively weaker anti-inflammatory effects compared to other NSAIDs. Its analgesic efficacy is comparable to morphine in postoperative pain but without opioid-related adverse effects such as respiratory depression, sedation, or dependence potential.

High-yield for exams
  • Ketorolac is limited to 5 days maximum (IV/IM + oral combined) due to GI bleeding and renal toxicity risks.
  • Contraindicated in active peptic ulcer disease, advanced renal impairment, and perioperative CABG surgery.
  • Nonselective COX inhibitor with analgesic potency comparable to morphine but without respiratory depression.
  • Black box warnings include GI bleeding, renal failure, increased bleeding risk, and cardiovascular thrombotic events.
  • Contraindicated with concurrent aspirin, other NSAIDs, anticoagulants, or probenecid due to additive toxicity.
  • Inhibits platelet function reversibly; bleeding time normalizes 24-48 hours after discontinuation.
  • Pregnancy category D in third trimester; risk of premature ductus arteriosus closure and oligohydramnios.
  • Commonly used as opioid-sparing agent in postoperative and renal colic pain management.

Indications

Ketorolac is indicated for the short-term (up to 5 days) management of moderate-to-severe acute pain that requires analgesia at the opioid level. It is particularly useful in postoperative pain management and serves as an opioid-sparing agent.

Common clinical uses:

  • Postoperative pain (surgical procedures)
  • Acute musculoskeletal pain
  • Renal colic pain (though caution is needed in renal impairment)
  • Acute migraine or severe headache (off-label)
  • Trauma-related pain

Ketorolac is available in multiple formulations: intravenous, intramuscular, oral, and ophthalmic (for ocular inflammation and pain following cataract surgery). The parenteral route is commonly used in emergency and perioperative settings for rapid onset of analgesia.

Ketorolac is not indicated for chronic pain conditions, minor or chronic pain, or as prophylactic analgesia before major surgery due to bleeding risk. Duration of therapy should never exceed 5 days (combined IV/IM and oral) due to cumulative toxicity risks.

Pharmacokinetics

Ketorolac exhibits predictable pharmacokinetic properties across its formulations:

Absorption: Oral ketorolac is rapidly and completely absorbed with peak plasma concentrations reached in 30-60 minutes. Bioavailability approaches 100%. IM and IV administration provide faster onset, with IM peaks at 30-60 minutes and IV providing immediate effect.

Distribution: Ketorolac is highly protein-bound (>99%, primarily to albumin) with a volume of distribution of approximately 0.15-0.33 L/kg. It crosses the placenta and appears in breast milk in low concentrations.

Metabolism: Ketorolac undergoes hepatic metabolism via glucuronidation and hydroxylation. Less than 50% is metabolized; the remainder is excreted unchanged.

Elimination: The primary route of elimination is renal (91%, with 60% as unchanged drug). The elimination half-life is 4-6 hours in healthy adults but is prolonged in elderly patients (up to 7 hours) and those with renal impairment. Dosing adjustments follow the product label for age and renal function.

Pharmacokinetic parameters are significantly altered in renal impairment, requiring dose reduction or avoidance.

Adverse effects

Ketorolac carries significant adverse effect risks, particularly with prolonged use beyond the recommended 5-day limit.

Gastrointestinal effects

  • Gastrointestinal bleeding and ulceration (most serious; black box warning)
  • Dyspepsia, nausea, abdominal pain
  • Peptic ulcer disease
  • Perforation and peritonitis (rare but life-threatening)

Renal effects

  • Acute kidney injury and acute renal failure
  • Reduced renal perfusion (via prostaglandin inhibition)
  • Fluid retention and edema
  • Hyperkalemia
  • Interstitial nephritis

Hematologic effects

  • Increased bleeding risk due to platelet inhibition
  • Prolonged bleeding time
  • Postoperative hemorrhage
  • Inhibition of platelet function (reversible, unlike aspirin)

Cardiovascular effects

  • Hypertension
  • Edema
  • Possible increased risk of thrombotic events (MI, stroke) with prolonged use

Hepatic effects

  • Elevated liver enzymes (AST, ALT)
  • Hepatotoxicity (rare)

Hypersensitivity reactions

  • Anaphylaxis and anaphylactoid reactions
  • Bronchospasm (especially in aspirin-sensitive asthma patients)
  • Stevens-Johnson syndrome and toxic epidermal necrolysis (rare)
  • Angioedema

Central nervous system

  • Headache, dizziness, drowsiness
  • Aseptic meningitis (rare)

Ophthalmic formulation

  • Transient stinging and burning
  • Corneal edema or erosion
  • Delayed wound healing

The risk of adverse effects increases with higher doses, longer duration, advanced age, and concurrent use of anticoagulants or corticosteroids.

Contraindications and warnings

Ketorolac carries multiple black box warnings and is contraindicated in numerous high-risk conditions.

Black box warnings

  • Gastrointestinal risk: Increased risk of serious GI adverse events including bleeding, ulceration, and perforation, which can be fatal. Risk increases with duration of use, in the elderly, and in patients with prior peptic ulcer disease or GI bleeding.
  • Bleeding risk: Ketorolac inhibits platelet function and is contraindicated as prophylactic analgesia before major surgery and perioperatively when hemostasis is critical.
  • Renal risk: Risk of renal impairment, including acute renal failure, especially in volume-depleted patients or those with pre-existing renal disease.
  • Cardiovascular risk: NSAIDs may increase risk of serious cardiovascular thrombotic events, MI, and stroke.

Absolute contraindications

  • Active peptic ulcer disease or recent GI bleeding
  • Advanced renal impairment (creatinine clearance <30 mL/min) or risk of renal failure due to volume depletion
  • Cerebrovascular bleeding, hemorrhagic diathesis, or incomplete hemostasis
  • History of NSAID-induced asthma, urticaria, or allergic reactions
  • Perioperative pain in the setting of coronary artery bypass graft (CABG) surgery
  • Labor and delivery (inhibits uterine contractions)
  • Concomitant use with aspirin, other NSAIDs, or probenecid
  • Patients receiving pentoxifylline due to increased bleeding risk
  • Neuraxial (epidural or intrathecal) administration

Pregnancy and lactation

Ketorolac is FDA pregnancy category C (first and second trimesters) and category D (third trimester). It should be avoided in late pregnancy due to risk of premature closure of the ductus arteriosus, oligohydramnios, and inhibition of labor. Small amounts appear in breast milk; use caution or avoid during breastfeeding.

Special populations

  • Elderly: Increased risk of GI bleeding, renal toxicity, and cardiovascular events; dose reduction recommended
  • Pediatric: Safety and efficacy not established in children under 2 years (ophthalmic) or under 17 years (systemic)
  • Hepatic impairment: Use with caution; avoid in severe hepatic disease

Maximum duration of therapy is 5 days (total combined parenteral and oral use).

Drug interactions

Ketorolac has numerous clinically significant drug interactions that increase risks of bleeding, nephrotoxicity, and other adverse effects.

Anticoagulants and antiplatelets

  • Warfarin, heparin, direct oral anticoagulants (DOACs): Increased bleeding risk; avoid concurrent use
  • Aspirin, clopidogrel, other antiplatelets: Additive antiplatelet effects and GI bleeding risk; contraindicated
  • Other NSAIDs: Increased GI and renal toxicity; contraindicated

Antihypertensives

  • ACE inhibitors, ARBs: Reduced antihypertensive efficacy; increased risk of acute renal failure, especially in volume depletion
  • Diuretics: Reduced diuretic efficacy; increased nephrotoxicity risk
  • Beta-blockers: Reduced antihypertensive effect

Nephrotoxic agents

  • Aminoglycosides, cyclosporine, tacrolimus: Additive nephrotoxicity
  • Lithium: Ketorolac reduces lithium clearance, increasing lithium levels and toxicity risk
  • Methotrexate: Reduced methotrexate clearance, increasing toxicity risk

Other interactions

  • Probenecid: Contraindicated; decreases ketorolac clearance, increasing plasma levels and toxicity
  • Pentoxifylline: Increased bleeding risk; contraindicated
  • Selective serotonin reuptake inhibitors (SSRIs), SNRIs: Increased GI bleeding risk
  • Corticosteroids: Increased risk of GI ulceration and bleeding
  • Alcohol: Increased GI bleeding risk

Pharmacodynamic considerations

Concurrent use of multiple drugs that affect hemostasis (anticoagulants, antiplatelets, SSRIs) significantly amplifies bleeding risk. Careful monitoring or avoidance is essential.

Clinical pearls

  • Opioid-sparing strategy: Ketorolac is highly effective for postoperative pain and can reduce opioid requirements by 30-50%, minimizing opioid-related side effects such as nausea, constipation, and respiratory depression.
  • Five-day limit is absolute: The maximum combined duration of IV/IM and oral ketorolac is 5 days. This limit exists to minimize cumulative GI, renal, and bleeding risks. Exceeding this duration significantly increases adverse event rates.
  • Renal colic: Ketorolac is commonly used in emergency departments for renal colic pain, providing analgesia comparable to opioids. However, it should be used cautiously if renal function is compromised or if the patient is volume-depleted.
  • Not for chronic pain: Ketorolac is strictly for acute pain management. It should never be used for chronic conditions due to the high risk of serious adverse effects with prolonged use.
  • Bleeding time normalization: Unlike aspirin (which irreversibly inhibits platelets for 7-10 days), ketorolac's antiplatelet effect resolves within 24-48 hours after discontinuation as the drug is cleared.
  • Ophthalmic use: Ophthalmic ketorolac (0.4%, 0.5%) is used for ocular inflammation and pain after cataract surgery and for seasonal allergic conjunctivitis. Systemic absorption is minimal but can occur.
  • NSAID hypersensitivity triad: Patients with aspirin-exacerbated respiratory disease (asthma, nasal polyps, aspirin sensitivity) are at high risk for severe bronchospasm with ketorolac; it is contraindicated in this population.
  • Volume depletion caution: In perioperative or postoperative settings, ensure adequate hydration before administering ketorolac to reduce acute kidney injury risk, especially in elderly patients or those receiving diuretics.
  • Transition strategy: When transitioning from parenteral to oral ketorolac, the total combined duration must not exceed 5 days. Oral dosing follows the product label and is typically lower than parenteral doses.
  • CABG contraindication: Ketorolac is contraindicated for perioperative pain management in CABG surgery due to increased risk of cardiovascular thrombotic events and bleeding complications, consistent with the class effect of NSAIDs.

Practice questions

1. A 62-year-old man undergoes elective cholecystectomy. Postoperatively, he receives intravenous ketorolac for pain control. On postoperative day 3, he develops melena and hematemesis. Laboratory studies show hemoglobin 8.2 g/dL (baseline 14 g/dL) and BUN 45 mg/dL. Upper endoscopy reveals multiple gastric ulcers with active bleeding. Which property of ketorolac most directly contributed to this complication?

Answer: B. Ketorolac is a nonselective NSAID that inhibits both COX-1 and COX-2 enzymes. COX-1 inhibition reduces constitutive prostaglandin synthesis in the gastric mucosa, removing the protective effect of prostaglandins on gastric acid secretion, mucus production, and mucosal blood flow, leading to ulceration. Additionally, ketorolac's antiplatelet effect from COX-1 inhibition impairs hemostasis, increasing bleeding risk from ulcers. This mechanism explains the black box warning for GI bleeding. Selective COX-2 inhibitors (option A) were developed to reduce this risk but ketorolac is nonselective.

2. A 45-year-old woman presents to the emergency department with severe right flank pain radiating to the groin, consistent with renal colic. She has a history of hypertension treated with lisinopril. The physician considers administering intravenous ketorolac for pain control. Laboratory studies show creatinine 1.8 mg/dL (baseline 1.1 mg/dL). Which mechanism best explains the contraindication to ketorolac in this patient?

Answer: A. Ketorolac inhibits COX enzymes, reducing synthesis of vasodilatory prostaglandins (PGE2, PGI2) in the kidney. These prostaglandins maintain renal blood flow and glomerular filtration rate, especially in states of reduced renal perfusion or pre-existing renal impairment. In this patient with elevated creatinine (1.8 mg/dL) and concurrent ACE inhibitor use (which reduces efferent arteriole tone), ketorolac can precipitate acute kidney injury by further compromising renal perfusion. Ketorolac is contraindicated in advanced renal impairment (CrCl <30 mL/min) and should be used cautiously in patients with baseline renal dysfunction or on ACE inhibitors.

3. A 28-year-old woman at 36 weeks gestation presents with severe headache and is diagnosed with preeclampsia. Her obstetrician considers analgesic options for pain control. Ketorolac is specifically contraindicated in late pregnancy primarily because of which fetal complication?

Answer: B. NSAIDs including ketorolac are contraindicated in the third trimester (FDA pregnancy category D) because prostaglandins maintain patency of the fetal ductus arteriosus. COX inhibition by ketorolac can cause premature constriction or closure of the ductus arteriosus in utero, leading to pulmonary hypertension and right heart failure. Additionally, prostaglandin inhibition reduces fetal renal perfusion and urine production, potentially causing oligohydramnios. NSAIDs also inhibit uterine contractions and can prolong labor. While ketorolac does increase bleeding risk via platelet inhibition, the primary fetal concern is ductal closure, making option B correct.

Frequently asked questions

How does ketorolac work?

Ketorolac works by nonselectively inhibiting both COX-1 and COX-2 enzymes, blocking the synthesis of prostaglandins that mediate pain and inflammation. This mechanism provides potent analgesia comparable to opioids but without opioid-related side effects like respiratory depression or sedation. However, COX-1 inhibition also reduces protective prostaglandins in the stomach and kidneys, leading to increased risks of GI bleeding and renal impairment.

What are the side effects of ketorolac?

The most serious side effects of ketorolac include gastrointestinal bleeding and ulceration, acute kidney injury, and increased bleeding risk due to platelet inhibition. Other common adverse effects include nausea, dyspepsia, edema, hypertension, and elevated liver enzymes. Rare but severe reactions include anaphylaxis, bronchospasm (especially in aspirin-sensitive individuals), Stevens-Johnson syndrome, and cardiovascular thrombotic events. The risk of these adverse effects increases significantly with use beyond the recommended 5-day limit.

Is ketorolac a controlled substance?

No, ketorolac is not a controlled substance. It is a nonsteroidal anti-inflammatory drug (NSAID) and does not have abuse potential or cause physical dependence like opioids. However, it is a prescription-only medication due to its significant risks of serious adverse effects including GI bleeding, renal impairment, and increased bleeding risk. Its use is strictly limited to short-term (maximum 5 days) management of moderate-to-severe acute pain.

Ketorolac vs ibuprofen — what is the difference?

Ketorolac is significantly more potent than ibuprofen and is used for moderate-to-severe acute pain, with analgesic efficacy comparable to opioids. Unlike ibuprofen, ketorolac is limited to 5 days of use due to higher risks of GI bleeding, renal toxicity, and bleeding complications. Ketorolac is available in parenteral (IV/IM) formulations for hospital use, while ibuprofen is primarily oral and available over-the-counter. Both are nonselective COX inhibitors, but ketorolac's greater potency comes with a less favorable safety profile for prolonged use.

Why is ketorolac limited to 5 days?

Ketorolac is limited to 5 days because prolonged use significantly increases the risk of serious adverse effects including gastrointestinal bleeding and ulceration, acute kidney injury, and bleeding complications. Clinical trials and post-marketing surveillance have demonstrated that adverse event rates rise sharply beyond 5 days of use. This strict duration limit is reflected in black box warnings and is designed to balance ketorolac's potent analgesic benefits against its cumulative toxicity risks, particularly in the GI tract, kidneys, and hemostatic system.

Conditions it is used for

Postoperative painAcute musculoskeletal painRenal colicTrauma painAcute migraineAcute headacheOcular inflammationAllergic conjunctivitis
IbuprofenNaproxenDiclofenacIndomethacinCelecoxibAspirinMorphineAcetaminophen

Sources and further reading

DailyMed (FDA labels)StatPearls (NCBI Bookshelf)MedlinePlusWHO ATC/DDD index: M01AB15WHO ATC/DDD index: S01BC05

Educational content for medical students, prepared by the WhiteCoat Pro editorial team with AI assistance; every page is reviewed by a second AI model for factual errors. It is not medical advice and does not replace the product label, local guidelines or a clinician.